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The equilibrium adsorption isotherms on two otherwise identical polymers, one imprinted with Fmoc-L-tryptophan (Fmoc-L-Trp) (MIP), the other nonimprinted (NIP), of compounds that are structural analogues of the template were acquired by frontal analysis (FA) in an acetonitrile/ acetic acid (99/1 v/v) mobile phase, over a wide concentration range (from 0.005 to 50 mM). These analogues were Fmoc-L-tyrosine, Fmoc-L-serine, Fmoc-L-phenyalanine, Fmoc-glycine (Fmoc-Gly), Fmoc-L-tryptophan pentafluorophenyl ester (Fmoc-L-Trp(OPfp)), and their antipodes. These substrates have different numbers of functional groups able to interact with the 4-vinylpyridine groups of the polymer. For a given number of the functional groups, these substrates have different hydrophobicities of their side groups (as indicated by their partition coefficients (log [P.sub.OW]) in the octanol-water system (e.g., from 4.74 for Fmoc-Trp to 2.53 for Fmoc-Gly)). Statistical results from the fitting of the FA data to Langmuirian isotherm models, the calculation of the affinity energy distribution, and the comparison of calculated and experimental band profiles show that all these sets of FA data are best accounted for by a tri-Langmuir isotherm model, except for the data of Fmoc-L-Trp(OPfp) that are best modeled by a simple Langmuir isotherm. So, all compounds but Fmoc-L-Trp(OPfp) find three different types of adsorption sites on both the MIP and the NIP. The properties of these different types of sites were studied systematically. The results show that the affinity of the structural analogues for the NIP is controlled mostly by the number of the functional groups on the substrates and somewhat by the hydrophobicity of their side groups. These two factors control also the MIP affinity toward the enantiomers of the structural analogues that have a stereochemistry different from that of the template. In contrast, the affinity of the highest affinity sites of the MIP toward the enantiomers of these structural analogues that have the same stereochemistry as the template is highest for the imprinted molecule (Fmoc-L-Trp). The separation of the template from the substrates with the same stereochemistry is influenced by the number of the functional groups on the substrates that can interact with the highest affinity sites on the MIP. The separation of the enantiomers of the analogues of the substrates was also achieved on the MIP, and these enantiomeric separations are influenced by the hydrophobicity of the substrates.

A new quantitative structure-activity relationship (QSAR) examination on benzodiazepine compounds(BDZs) to gamma-aminobutyric acid receptor (GABA)/ benzodiazepine receptor (BZR) is presented. The study states that for different kinds of benzodiazepine receptor (BZR) ligands, certain crucial features in each kind of ligands is featured, without which they would not be able to interact with the receptor at all.

The sorting of transmembrane proteins to endosomes and lysosomes is mediated by signals present in the cytosolic tails of the proteins. A subset of these signals conform to the [DE]XXXL[LI] consensus motif and mediate sorting via interactions with heterotetrameric adaptor protein (AP) complexes. However, the identity of the AP subunits that recognize these signals remains controversial. We have used a yeast three-hybrid assay to demonstrate that [DE]XXXL[LI]-type signals from the human immunodeficiency virus negative factor protein and the lysosomal integral membrane protein II interact with combinations of the [gamma] and [sigma]1 subunits of AP-1 and the [delta] and [sigma]3 subunits of AP-3, but not the analogous combinations of AP-2 and AP-4 subunits. The sequence requirements for these interactions are similar to those for binding to the whole AP complexes in vitro and for function of the signals in vivo. These observations reveal a novel mode of recognition of sorting signals involving the [gamma]/[delta] and [sigma] subunits of AP-1 and AP-3.

The transcription factor and tumour suppressor p53 and its two homologues p63 and p73 form a family of proteins. p63 and p73 show much greater molecular complexity than p53 because they are expressed both as multiple alternatively spliced C-terminal isoforms, and as N-terminally deleted, dominant-negative proteins that show reciprocal functional regulation. In addition, several other factors, such as post-translational modifications and specific and common family regulatory proteins, result overall in subtle modulation of their biological effects. Although all p53, p63 and p73 family members are regulators of the cell cycle and apoptosis, the developmental abnormalities of p73- and p63-null mice do not show enhanced tumour susceptibility of p53 knockouts, suggesting that complex regulatory processes modulate the functional effects of this family of proteins.

The type IV bundle-forming pili (BFP) of enteropathogenic Escherichia coli (EPEC) are required for virulence in orally challenged human volunteers and for the localized adherence and autoaggregation in vitro phenotypes. BFP filament biogenesis and function are encoded by the 14-gene bfp operon. The BFP assembly complex, containing a [BfpB-His.sub.6] fusion protein, was chemically cross-linked in situ, and the complex was then purified from BFP-expressing EPEC by a combination of nickel- and BfpB antibody-based affinity chromatography. Characterization of the isolated complex by immunoblotting using BFP protein-specific antibodies showed that at least 10 of the 14 proteins specified by the bfp operon physically interact to form an oligomeric complex. Proteins localized to the outer membrane, inner membrane, and periplasm are within this complex, thus demonstrating that the complex spans the periplasmic space. A combination of immunofluorescence and immuno-gold thin-section transmission electron microscopy studies localized this complex to one pole of the cell.

The Synechocystis sp. strain PCC 6803, which has a T192H mutation in the D2 protein of photosystem II, is an obligate photoheterotroph due to the lack of assembled photosystem II complexes. A secondary mutant, Rg2, has been selected that retains the T192H mutation but is able to grow photoautotrophically. Restoration of photoautotrophic growth in this mutant was caused by early termination at position 294 in the Slr2013 protein. The T192H mutant with truncated Slr2013 forms fully functional photosystem II reaction centers that differ from wild-type reaction centers only by a 30% higher rate of charge recombination between the primary electron acceptor, [Q.sub.A.sup.-], and the donor side and by a reduced stability of the oxidized form of the redox-active Tyr residue, [Y.sub.D], in the D2 protein. This suggests that the T192H mutation itself did not directly affect electron transfer components, but rather affected protein folding and/or stable assembly of photosystem II, and that Slr2013 is involved in the folding of the D2 protein and the assembly of photosystem II. Besides participation in photosystem II assembly, Slr2013 plays a critical role in the cell, because the corresponding gene cannot be deleted completely under conditions in which photosystem II is dispensable. Truncation of Slr2013 by itself does not affect photosynthetic activity of Synechocystis sp. strain PCC 6803. Slr2013 is annotated in CyanoBase as a hypothetical protein and shares a DUF58 family signature with other hypothetical proteins of unknown function. Genes for close homologues of Slr2013 are found in other cyanobacteria (Nostoc punctiforme, Anabaena sp. strain PCC 7120, and Thermosynechococcus elongatus BP-1), and apparent orthologs of this protein are found in Eubacteria and Archaea, but not in eukaryotes. We suggest that Slr2013 regulates functional assembly of photosystem II and has at least one other important function in the cell.

Adenosine kinase (AK) is a purine salvage enzyme that catalyzes the phosphorylation of adenosine to AMP. In Mycobacterium tuberculosis, AK can also catalyze the phosphorylation of the adenosine analog 2-methyladenosine (methyl-Ado), the first step in the metabolism of this compound to an active form. Purification of AK from M. tuberculosis yielded a 35-kDa protein that existed as a dimer in its native form. Adenosine (Ado) was preferred as a substrate at least 30-fold ([K.sub.m]= 0.8[+ or -]0.08[micro]M) over other natural nucleosides, and substrate inhibition was observed when Ado concentrations exceeded 5 [micro]M. M. tuberculosis and human AKs exhibited different affinities for methyl-Ado, with [K.sub.m] values of 79 and 960 [micro]M, respectively, indicating that differences exist between the substrate binding sites of these enzymes. ATP was a good phosphate donor ([K.sub.m]=1100[+ or -]140[micro]M; however, the activity levels observed with dGTP and GTP were 4.7 and 2.5 times the levels observed with ATP, respectively. M. tuberculosis AK activity was dependent on [Mg.sup.2+], and activity was stimulated by potassium, as reflected by a decrease in the [K.sub.m] and an increase in [V.sub.max.] for both Ado and methyl-Ado. The N-terminal amino acid sequence of the purified enzyme revealed complete identity with Rv2202c, a protein currently classified as a hypothetical sugar kinase. When an AK-deficient strain of M. tuberculosis (SRICK1) was transformed with this gene, it exhibited a 5,000-fold increase in AK activity compared to extracts from the original mutants. These results verified that the protein that we identified as AK was coded for by Rv2202c. AK is not commonly found in bacteria, and to the best of our knowledge, M. tuberculosis AK is the first bacterial AK to be characterized. The enzyme shows greater sequence homology with ribokinase and fructokinase than it does with other AKs. The multiple differences that exist between M. tuberculosis and human AKs may provide the molecular basis for the development of nucleoside analog compounds with selective activity against M. tuberculosis.

Highly conserved glycine residues within span I and span II of the phenylalanine and tyrosine transporter PheP were shown to be important for the function of the wild-type protein. Replacement by amino acids with increasing side chain volume led to progressive loss of transport activity. Second-site suppression studies performed with a number of the primary mutants revealed a tight packing arrangement between spans I and acid-polyamine-organocation family, may function as a dimerization motif. Surprisingly, other highly conserved residues, such as Y60 and L41, could be replaced by various residues with no apparent loss of activity.

POTRA (for polypeptide-transport-associated domain) is a novel domain identified in proteins of the ShlB, Toc75, D15 and FtsQ/DivlB families. In most cases, the POTRA domain is associated with a [beta]-barrel outer membrane domain and its function has been experimentally related to polypeptide transport in Toc75 (Tic-Toc protein import system in chloroplast) and ShlB families. In addition to potential key roles in protein transport across the outer membrane and in bacterial septation, the POTRA domain has attractive features for vaccine development in diseases such as cholera, meningitis, gonorrhoea and syphilis.

Activators of [[sigma]sup.54]-RNA polymerase holoenzyme couple ATP hydrolysis to formation of an open promoter complex. [DCtD.sub.[DELTA]1-142], a truncated and constitutively active form of the [sigma]sup.54]-dependent activator DctD from Sinorhizobium meliloti, displayed an altered DNase I footprint at its binding site located upstream of the dctA promoter in the presence of ATP. The altered footprint was not observed for a mutant protein with a substitution at or near the putative arginine finger, a conserved arginine residue thought to contact the nucleotide. These data suggest that structural changes in [DCtD.sub.[DELTA]1-142] during ATP hydrolysis can be detected by alterations in the DNase I footprint of the protein and may be communicated by interactions between bound nucleotide and the arginine finger. In addition, kinetic data for changes in fluorescence energy transfer upon binding of 2'(3')-O-(N-methylanthraniloyl)-ATP (Mant-ATP) to [DCtD.sub.[DELTA]1-142] and DctD suggested that these proteins undergo multiple conformational changes following ATP binding.

The response regulator VirR and its cognate sensor histidine kinase, VirS, are responsible for toxin gene regulation in the human pathogen Clostridium perfringens. The C-terminal domain of VirR (VirRc) contains the functional FxRxHrS motif, which is involved in DNA binding and is conserved in many regulatory proteins. VirRc was cloned, purified, and shown by in vivo and in vitro studies to comprise an independent DNA binding domain. Random and site-directed mutagenesis was used to identify further amino acids that were required for the functional integrity of the protein. Random mutagenesis identified a unique residue, Met-172, that was required for biological function. Site-directed mutagenesis of the SKHR motif (amino acids 216 to 219) revealed that these residues were also required for biological activity. Analysis of the mutated proteins indicated that they were unable to bind to the DNA target with the same efficiency as the wild-type protein.

TonB, in complex with ExbB and ExbD, is required for the energy-dependent transport of ferric siderophores across the outer membrane of Escherichia coli, the killing of cells by group B colicins, and infection by phages T1 and [sigma]80. To gain insights into the protein complex, TonB dimerization was studied by constructing hybrid proteins from complete TonB (containing amino acids 1 to 239) [TonB(1-239)] and the cytoplasmic fragment of ToxR which, when dimerized, activates the transcription of the cholera toxin gene ctx. ToxR(1-182)-TonB(1239) activated the transcription of lacZ under the control of the ctx promoter ([P.sub.ctx]::lacZ). Replacement of the TonB transmembrane region by the ToxR transmembrane region resulted in the hybrid proteins ToxR(1210)-TonB(33-239) and ToxR(1-210)-TonB(164-239), of which only the latter activated [P.sub.ctx]::lacZ transcription. Dimer formation was reduced but not abolished in a mutant lacking ExbB and ExbD, suggesting that these complex components may influence dimerization but are not strictly required and that the N-terminal cytoplasmic membrane anchor and the C-terminal region are important for dimer formation. The periplasmic TonB fragment, TonB(33-239), inhibits ferrichrome and ferric citrate transport and induction of the ferric citrate transport system. This competition provided a means to positively screen for TonB(33-239) mutants which displayed no inhibition. Single point mutations of inactive fragments selected in this manner were introduced into complete TonB, and the phenotypes of the TonB mutant strains were determined. The mutations located in the C-terminal half of TonB, three of which (Y163C, V188E, and R204C) were obtained separately by site-directed mutagenesis, as was the isolated F230V mutation, were studied in more detail. They displayed different activity levels for various TonB-dependent functions, suggesting function-related specificities which reflect differences in the interactions of TonB with various transporters and receptors.

Vesicle affinity capillary electrophoresis (VCE), a newly developed technique, was designed to assess the effect of physicochemical properties of apolipoprotein (apo) on the binding to lipoproteins, under physiological conditions (phosphate--saline buffer system at pH 7.4 and 37[degrees]C), using vesicle as a model. The technique results in similar lipid binding properties of apo CIII (CIII) and its peptides compared to other techniques. (l,2) It also offers a fast and more sensitive tool in determining the lipid affinity of apos in a unique system simulating the dynamic binding properties of apo in vivo. A noncompetitive binding model is used to determine the multiple binding properties of CIII and its peptides to vesicle. The VCE binding constants are dependent on temperature, physicochemical properties of the protein (hydrophobicity and charge), and nature of the vesicle. The vesicles used in the VCE experiments described here have been fully characterized and found to be stable under different temperatures (4 and 37[degrees]C) and voltage conditions. Migration behavior of CIlI and related peptides is reported in terms of relative mobility in order to correct for variability in viscosity at different vesicle concentrations. The VCE method provides very precise data on the migration time from 0.1 to 3.3% RSD at the highest concentration of vesicle. The model and current data have been used to determine VCE binding constants and protein-to-lipid binding ratios. The model predicts that higher lipid affinity ([K.sub.B]), protein--lipid binding ratio (n), and lower protein concentration result in a shift of the binding isotherm toward a lower concentration range of vesicle. A higher vesicle mobility, reflecting the size and charge of the vesicle, results in a larger separation window between the migration time of the free protein and the complex. The value of VCE for structure--function studies and drug design for peptides and proteins that are strongly bound to lipids has been illustrated.

Stem cells (SCs) are functionally defined by their abilities to self-renew and generate differentiated cells. Although much effort has been focused on defining the common characteristics among various types of SCs, the genetic and functional differences between multipotent and pluripotent SCs have garnered less attention. We report a direct genetic and functional comparison of molecularly defined and clonally related populations of neural SCs (NSCs) and embryonic SCs (ESCs), using the Sox2 promoter for isolation of purified populations by fluorescence-activated cell sorting. A stringent expression profile comparison of promoter-defined NSCs and ESCs revealed a striking dissimilarity, and subsequent chimera analyses confirmed the fundamental differences in cellular potency between these populations. This direct comparison elucidates the molecular basis for the functional differences in pluripotent ESCs and multipotent NSCs.

Research reveals that unstructured proteins arise from expansion of internal repeat regions as seen in a preponderance of repeats in 126 protein sequences. Data indicate that tandemly repeated segments account for 39% in Swiss-Prot, 18% in yeast and 28% in human proteins. Furthermore, the repetitive segments are involved in fundamental functions of the unstructured proteins.

This review discusses the function of Y-box-binding protein-1, belonging to the cold-shock domain protein superfamily, in a environmental stress reactions. Results describes properties of the YB-1 and the pleiotropic functions mediated by DNA-RNA transaction and protein-protein interactions. Furthermore, YB-1 is known to be mediating a diverse range of physiological and pathological functions.

Understanding the relationship between the structural and functional organization of the human brain is one of the most important goals of neuroscience. Individual variability in brain structure means that it is essential to obtain this information from the same subject. To date, this has been almost impossible. Even though noninvasive functional imaging techniques such as functional MRI (fMRI) are now commonplace, there is no complementary noninvasive structural technique. We present an in vivo method of examining the detailed neuroanatomy of any individual, which can then be correlated with that individual's own functional results. This method utilizes high-resolution structural MRI to identify distinct cortical regions based on cortical lamination structure. We demonstrate that the observed MR lamination patterns relate to myeloarchitecture through a correlation of histology with MRI. In vivo high-resolution MRI studies identify striate cortex, as well as visual area V5, in four individuals, as defined by using fMRI. The anatomical identification of a cortical area (V5/MT) outside of striate cortex is a significant advance, proving it possible to identify extra-striate cortical areas and demonstrating that in vivo structural mapping of the human cerebral cortex is possible.

The [beta]/[alpha] barrel is the common protein fold of numerous enzymes and was proposed recently to be the result of gene duplication and fusion of an ancient half-barrel. The initial enzyme of shikimate biosynthesis possesses the additional feature of feedback regulation. The crystal structure and kinetic studies on chimera and mutant proteins of yeast 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) synthase from Saccharomyces cerevisiae inhibited by phenylalanine (Aro3p) and DAHP synthase S. cerevisiae inhibited by tyrosine (Aro4p) give insight into important regions for regulation in the enzyme: The loop, which is connecting the two half-barrels, and structural elements added to the barrel are prerequisites for regulation and form a cavity on the N-terminal side of the [beta]/[alpha] barrel. In the cavity of Aro4p at position 226 is a glycine residue, which is highly conserved in all other tyrosine-regulated DAHP synthases as well. Sequence alignments with phenylalanine-regulated DAHP synthases including Aro3p show a highly conserved serine residue at this position. An exchange of glycine to serine and vice versa leads to a complete change in the regulation pattern. Therefore the evolution of these differently feedback-inhibited isoenzymes required gene duplication and a single mutation within the internal extra element. Numerous additional amino acid substitutions present in the contemporary isoenzymes are irrelevant for regulation and occurred independently.

[F.sub.1][F.sub.o]-ATP synthase is the enzyme responsible for most of the ATP synthesis in living systems. The catalytic domain [F.sub.1] of the [F.sub.1][F.sub.o] complex, [F.sub.1]-ATPase, has the ability to hydrolyze ATP. A fundamental problem in the development of a detailed mechanism for this enzyme is that it has not been possible to determine experimentally the relation between the ligand binding affinities measured in solution and the different conformations of the catalytic [beta] subunits ([[beta].sub.TP], [[beta].sub.DP],[[beta].sub.E]) observed in the crystal structures of the mitochondrial enzyme, M[F.sub.1]. Using free energy difference simulations for the hydrolysis reaction ATP+[H.sub.2]O [right arrow] ADP+[P.sub.i] in the [[beta].sub.TP] and [[beta].sub.DP] sites and unisite hydrolysis data, we are able to identify [[beta].sub.TP] as the 'tight' ([K.sub.D] = [10.sup.-12] M, M[F.sub.1]) binding site for ATP and [[beta].sub.DP] as the 'loose' site. An energy decomposition analysis demonstrates how certain residues, some of which have been shown to be important in catalysis, modulate the free energy of the hydrolysis reaction in the [[beta].sub.TP] and [[beta].sub.DP] sites, even though their structures are very similar. Combined with the recently published simulations of the rotation cycle of [F.sub.1]-ATPase, the present results make possible a consistent description of the binding change mechanism of [F.sub.1]-ATPase at an atomic level of detail.

A striking property of speech perception is its resilience in the face of acoustic variability (among speech sounds produced by different speakers at different times, for example). The robustness of speech perception might, in part, result from multiple, complementary representations of the input, which operate in both acoustic--phonetic feature-based and articulatory--gestural domains. Recent studies of the anatomical and functional organization of the non-human primate auditory cortical system point to multiple, parallel, hierarchically organized processing pathways that involve the temporal, parietal and frontal cortices. Functional neuroimaging evidence indicates that a similar organization might underlie speech perception in humans. These parallel, hierarchical processing `streams', both within and across hemispheres, might operate on distinguishable, complementary types of representations and subserve complementary types of processing. Two long-opposing views of speech perception have posited a basis either in acoustic feature processing or in gestural motor processing; the view put forward here might help reconcile these positions.

Molecular dynamics simulations point out that calmodulin-peptide complex displays loop regions as more flexible than helical regions with entropy loss per residue upon folding at 20% less for loops than for helices. Calculated amide and methyl angular generalized order parameters show agreement between amide order parameters at the highger temperature.

Mutagenesis analysis in the human retinal cone sodium/calcium-potassium exchanger protein reveals three classes of amino acid residues comprising of acidic, polar, and glycine residues are sensitive for mutagenesis. Data indicate that the mutation affects the sodium/calcium-potassium exchanger function.

Results indicate that the conserved residues R420 and Q428 in the cytoplasmic loop of the citrate/malate transporter CimH of Bacillus subtilis are either partly protruding to the exterior or a water-filled substrate translocation pathway extends to the cytoplasm-membrane interface in order to be exterrnally accessible.

Results reveal that in the three filamin isoforms investigated, the immunoglobulinlike domain is essential for dimerization, which increases by the introduction of hinge 2 region. Furthermore, heterodimers form between filamins b and c. The dimerization region is localized to the carboxy-teminus of the protein.

Results show that the disulfide-dimerized peptide exhibits increased permeabilization and antimicrobial activity than the monomeric peptide at low concentrations. Furthermore, the dimer releases more carboxyfluorescein. Taken together, data indicate that the dimeric peptide has a role in the structural diversity of antimicrobial peptides in frog skin.

Research indicates that the backbone of the plastocyanin from Anabaena variabilis is rigid but the regions which are involved in the protein's electron transfer function show moderate mobility. The mobility sites are localized to 'northern' hydrophobic site close to the metal site, the metal site itself, and the 'eastern' face of the protein.

Results show that native myoglobin assumes a true molten globule form on the addition of hexafluoroisopropanol, in which tertiary interactions are reduced, whereas the secondary structure and the globular compactness are conserved.

Experiments were done on several catalysts containing different organic ligands bonded to the titanium centers that were prepared, characterized and tested in the benchmark reaction of cyclohexene with hydrogen peroxide. The results show that the activity and selectiveness of the catalysts depend on the relative basicity of the ligands and their variation is proportional to the calculated Lewis acidity.

Uniformly sized molecularly imprinted polymers (MIPs) for (S)-nilvadipine have been prepared by a multistep swelling and polymerization method using methacrylic acid, 2-(trifiuoromethyl)acrylic acid, 2-vinylpyridine, or 4-vinylpyridine (4-VPY) as a functional monomer and ethylene glycol dimethacryiate (EDMA) as a cross-linker. The chiral recognition abilities of the MIPs for nilvadipine and other dihydropyridine calcium antagonists were evaluated using a mixture of sodium phosphate buffer (or water) and acetonitrile or only acetonitrile as the mobile phase. The (S)-nilvadipine-imprinted 4-VPY-co-EDMA polymers gave the highest resolution for nilvadipine among the MIPs prepared. In addition, the enantioseparation of nilvadipine was attained using the (S)-nilvadipine-imprinted EDMA polymers, without use of a functional monomer. (1) H NMR and molecular modeling studies suggested a one-to-one hydrogen-bonding-based complex formation of (S)-nilvadipine with 4-VPY in chloroform. These results reveal that the (S)-nilvadipineimprinted EDMA polymers could recognize the template molecule by its molecular shape, and that in addition to this recognition, hydrophobic and hydrogen-bonding interactions seems to play important roles in the retention and chiral recognition of nilvadipine on the 4-VPY-co-EDMA polymers in hydroorganic mobile phases. By optimizing chromatographic conditions such as column temperature and flow rate, the baseline separation of nilvadipine enantiomers was attained with a short analysis time and with a column efficiency comparable to commercially available chiral stationary phases based on a protein, such as ovomucoid or al-acid glycoprotein.

Research demonstrates the secretion of pro-transglutaminase by Corynebacterium glutamicum by coupling to signal peptides of the cell surface proteins of the bacterium. The pro-domain is processed by a subtilisin-like protease from Streptomyces albogriseolus. Data show that Corynebacterium glutamicum secretes two proteins that can be exploited for industrial-scale production.

Results demonstrate that the supramolecular structures of Abeta(sub)10-35, Abeta(sub)1-40, and Abeta(sub)1-42 fibrisls of the Alzheimer's beta-amyloid fibrils are very similar as shown by electron microscopy, scanning electron microscopy, and solid-state nuclear magnetic resonance measurements.

Research shows that the environmental toxin arsenite phosphorylates several amino acid residues in tau protein, which is again hyperphosphorylated under pathological conditions. Data do not pin point to the exact mechanism of arsinite induced tau phosphorylation but arsenite probably starts a cascade leading to deregulation of tau function as a neurodegeneration-mediating protein.

Results show that it is possible to incorporate a pharmacological profile of peptide toxins into the bacteril potassium channel protein and its chimeras carrying the mammalian subregion I of the corresponding channel protein.

Research demonstrates the use of the title compound for monitoring DNA condensation. Results show that the condensation by either polyethylenimine or cetyltrimethylammonium bromide results in freezing the segmental mobility of the helix, whereas by Co(NH(sub)3)(sub)6(sup)3+ increases the DNA flexibility.

Results suggest that the amino acid residues in the vicinity of the tyrosine of the reaction center can act as proton acceptors for the oxidized tyrosine in Rhodobacter sphaeroides as shown by amino acid substitution experiments.

Results reveal that the formation of the ternary complex moves the catalytic domain toward the coenzyme-binding domain subsequent to substrate binding leading to domian closure in glutathione-dependent formaldehyde dehydrogenase.

The modulation of the DNA binding effector domain of the response regulator, NarL, is dependent on the phosphorylation state of the receiver domain. Research shows that the mechanism of activation of NarL involves a disruption of the interdomain interface and the conformational status of the domains. The modulation is governed by the open or active state of the domains.

Results reveal that the C-terminus of the epsilon subunit of the ATP synthase plays a more important role in the enzyme regulation than in ATP synthesis as shown by the lack of influence of the truncated epsilon subunit on the ATP synthesis, but less inhibitory to the ATPase activity.

Research demonstrates that the light-induced trimer-to-monomer transition in light-harvesting complex II follows a thermo-optic mechanism involving a thermally mediated elementary structural transitions. Data indicate that disruption of trimers occurs in both lamellar aggregates of light-harvesting complex II and in photosystem II-enriched grana membranes.

Results show that the retinoblastoma pocket is bound by an L-shaped E2F-2 peptide, whose five residues involved in the transcription activity of E2F are masked by retinoblastoma upon binding to E2F. Data suggest a'direct binding and masking' in retinoblastoma-mediated E2F inhibition and explain the E2F transactivation domain is recognized by the retinoblastoma tumor suppressor.

Results poin out that the protein O-fucosyltransferase is an integral component of the Notch signaling pathway and is essential for activation of Notch by its ligands. Data from the Drosophila GDP-fucose protein O-fucosyltransferase 1 reveals that O-fucose is required for normal notch signaling.

Results show that a single active site in the eubacterium, Bacillus stearothermophilus, CCA-adding enzyme recognizes both ATP and CTP. Furthermore, as revealed by the crystal structure analysis, the enzyme exhibits four domains each is capable of switching its base between ATP and CTP during CCA-adding mechanism.

Results show that two key meiotic proteins, Red1 and Dmc1 play multiple roles in the structure and function of chromosomes during meiotic prophase. Data indicate that they mediate chiasma formation effecting changes at the DNA and chromosome-axis levels.

A comparative description of a recombinant and native proguanylin shows identical biophysical and structural features. Data reveal that both are monomeric in solution.

Results from homology modeling reveal that the heterotrimeric human G(sub)alpha proteins exhibit a basic, positively charged, structural motif at the N-termini, which influence both membrane affinity and orientation of the G proteins. Data further suggest that the alpha-helical basic motif participates in the membrane-targeting and palmitylation-determining signaling.

Results reveal that although autocatalysis and decarboxylation of S-adenosylmethionine decarboxylase requires putrescine in higher organisms, the enzyme from plant sources exhibit the above activities in the absence of putrescine. Data indicate that highly conserved negatively charged amino acids at the active site regulate the enzyme activity in the absence of putrescine.

Results show an anisotropic decay of substrates bound to cytochrome P450(sub)cam, indicating that the substrate mobility is influenced by physicochemical and protein-substrate interactions at the local active sites. Furthermore, the cytochrome's local and peripheral structural amenability and heterogeneity coupled with substrate mobility regulate substrate binding orientation during enzyme catalysis.

Amino acid valine 114 substitution in the elonagtion factor 1alpha from Sulfolobus solfataricus archaeon confers new activity on the mutant enzyme which is absent in the wild-type. Data indicate that the acidic and basic residues substitution markedly destabilizes the elongation factor, whereas the effect of cavity-forming residue substitution is only marginal.

Research demonstrates that atomic changes to the bovine purine nucleoside phosphorylase transition-state analogues changes the catalytic site contacts interactions in the enzyme. Data show that the analogue immucillins' tight binding is not due to a single hydrogen bond but is a result of a precise arrangement of hydrogen bond acceptor/donor patterns.