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The transcriptional coactivator protein CBP and its paralog p300 each contain two homologous zinc-containing TAZ (transcriptional adaptor zinc-binding) domains, which constitute the interaction sites for a number of transcription factors. Both the CBP and p300 TAZ domains in the presence of stoichiometric concentrations of Zn(super 2+) adopt a well-defined structure in solution in the absence of binding partners.

Heteronuclear NMR methods are used to probe the loop conformations in solution in complexes of dihydrofolate reductase (DHFR) formed during the catalytic cycle. The active site loop conformation and the occupancy of the substrate and cofactor binding sites in all intermediates formed in the extended catalytic cycle are characterized from the NMR data.

The N-terminal cysteine-rich somatomedin B (SMB) domain of the human glycoprotien vitronectin contains the high-affinity binding sites for plasminogen activator inhibitor-1(PAI-1) and the urokinase receptor (uPAR). The studies demonstrate that the three dimensional structure of the SMB domain is extremely compact and that the disulfide bonds are packed in the center of the domain forming a covalently bonded core.

Research has been conducted on the unfolded apomyoglobin. The NMR characterization of this apomyoglobin denaturated in urea has been carried out in investigating polypeptide's behavior under denaturing conditions and the details are presented.

Research has been conducted on the apomyoglobin folding pathways and intermediates. The role of the intrinsic helical properties in the apomyoglobin folding process has been examined via the mutant preparation in which Asn132 and Glu136 have been substituted with glycine and the results are discussed.

Research has been conducted on the enzyme catalytic mechanism. The effect of the polypeptide chain's local motion on this mechanism has been investigated via (super)15 N relaxation data measurements for Escherichia coli dihydrofolate reductase in different complexes which represent different stages in the enzyme catalytic cycle.

Research has been conducted on the apomyoglobin that forms a denatured state under low-salt conditions. The characterization of the conformational properties and the polypeptide backbone dynamics of this state via NMR spectroscopy is described.

Research has been conducted on the cellular prion protein. The dynamics of the prion protein fragments from Syrian hamster has been investigated via NMR relaxation measurements.

The dynamics of polypeptide chain near the active site of beta-lactamase may influence the binding of substrates and/or intermediates' stabilization during enzyme catalysis. Marked changes in the backbone and tryptophan indole dynamics are seen in the flap and minor loop of the enzyme in the presence and absence of tight-binding inhibitor, SB225666.

Apomyoglobin mutation, mediated by phenylalanine replacing the distal histidine64, while stabilizing the protein, it increases the overall rate of protein folding. Data further indicate that replacement of the polar histidine with a nonpolar type stabilizes the protein in the early stages of folding.

Research has been conducted on the Wilms' tumor suppressor protein. The effect of the posttranscriptional modification on this protein is described.

Research has been conducted on the apomyoglobin folded state at pH 4. The use of NMR spectroscopy in investigating the structure and dynamics of this intermediate state is discussed.

Metallo-beta-lactamase from Bacteroides fragilis has a hairpin loop next to the two zinc molecules at the catalytic site. This part of the enzyme may be very flexible, allowing it to bind to a variety of substrates.

The glycosylation of threonine of the repeating unit of RNA polymerase II with beta-linked N-acetylglucosame was investigated. Two analogues of the repeating C-terminal domain of RNA polymerase II were synthesized and their conformations in water were examined. Experimental results showed that glycosylation of the local, randomly coiled peptide with one biologically essential sugar results in the formation of a turnlike structure. The experiment was the first structural investigation of a novel class of glycoproteins monoglycosylated with N-acetylglucosamine on threonine.

The effects of chain length and the presence and absence of specific capping sequences were examined by studying a peptide of 31 residues consisting of the C-terminal sequence of the four-helix bundle protein myohemerythrin from themiste zostericola. Intact capping sequences increase the population of helix in the central portion of the peptide and limits helix formation to this sequence. Increased length and intact capping sequences were shown to be important in protein folding.

Nuclear magnetic resonance spectroscopy, enzymatic analysis, fluorimetry and UV spectrometry were performed to study the role of buried charged groups such as Asp 26 and Lys 57 in the redox mechanism of action of thioredoxin derived from Escherichia coli. The results revealed that the two buried charged groups, Asp 26 and Lys 57, play a significant role in maintaining the optimum redox catalytic activity of thioredoxin.

Thioredoxin from Escherichia coli has a highly conserved carboxyl group of aspartic acid 26 (asp26) on its active site which is difficult to assess for ionization constant (pKa) due to interference from the pH-dependent activities of nearby groups. Nuclear magnetic resonance methods which take into account the proton resonances between carbon-13 of the carbon monoxide of the titrating carboxyl group and a nearby group enabled the determination of the pKa of asp26, which is 7.3 to 7.5, rather than 9.0 as previously reported.

Rusticyanin has the classical 'blue-copper' coordination set of CysHis2Met. This was gleaned from the results of an experiment, wherein two site-specific mutants were prepared to investigate the identity of the fourth ligand in the phylogenetically conserved carboxy-terminal loop possessed by rusticyanin. Two of the proposed ligands in the mutants, Asp 73 and His 85, have been substituted with alanine. The Asp73Ala variant retained the electronic properties of the blue-copper center, while the His85Ala mutant yielded a green type 1 copper protein, affirming the presence of a cavity at the copper site.

Analysis of the electrospray spectrum, obtained from ion spray mass spectrometric analysis of the reaction of a catalytic antibody Fv fragment with ester substrates, reveals the presence of an antibody fragment denoting about 8% of the total concentration of Fv. Addition of p-nitrophenyl ester to Fv stimulates the generation of this fragment. The absence of this species during the addition of p-chlorophenyl ester substrate implies its dependence on the nature of the leaving group. The conclusions obtained from these studies are in accordance with the proposed multistep kinetic mechanism.

Modern NMR techniques enable the determination of the amide proton exchange rates in oxidized and reduced Escherichia coli thioredoxin. Backbone mobility of the amide proton is estimated from these exchange rates. Oxidized thioredoxin exhibits lower exchange rate for Cys 35 amide proton compared to reduced thioredoxin. The higher exchange rate for reduced forms reveals that reduction loosens the structure of the protein. Greater flexibility of the reduced form accounts for the functional differences between two forms.

A mixing method was used to examine the kinetics of the unfolding transition of French bean apoplastocyanin which has both unfolding and refolding transitions, and it was found to have an exclusive single-state transition. Two transitions with two separate speeds were observed and used for measuring the refolding reaction. An intermediate which has many features present in the molten globule is produced in the retarded folding interaction wherein the amide protons present in the beta-sheets are sheltered from exchange.

Circular dichaoism (CD) and nuclear magnetic resonance spectroscopy (NMR) studies of the folding properties of the Mb-G (Myoglobin) and the Mb-H (Myoglobin-H) peptides of the G and H helix segments of sperm whale myoglobin show that Mb-G possesses few helices in aqueous solution, while Mb-H has a significant helix population. NMR of Mb-H also indicates that Mb-H helices are in dynamic equilibrium with unfolded states, the equilibrium being dependent on solution concentrations. The relative helicity at various sites of the Mb-H peptide has also been studied.

A study of peptide fragments of sperm whale myoglobin, corresponding to the region between the G- and H- helices, in water and solvent mixtures of water and trifluoroethanol (TFE) indicates that turn sequences in proteins help in helix termination in TFE during the initial folding stages in the native protein. Mb-GH5 (Myoglobin-GH5), a five residue peptide, and Mb-GH25, a 25 residue peptide, turn conformation in aqueous solutions though there is no helix formation in the regions on either side of the residue sequence. The studies used circular dichroism (CD) and nuclear magnetic resonance spectroscopy (NMR) techniques.

The synthesis and study of a series of dilsulphide-bridged dimeric peptides with the entire G- and H-helix sequences of sperm whale myoglobin (Mb) analyzed the long-range interactions in protein folding after the formation of the initial secondary structure. CD spectra show that disulphide bridged peptides made of two H-helices (Mb-HssH) and one G-and one H-helix (Mb-GssH) form helices in waste due to intermolecular attraction. But Mb-GH51, a 51 residue peptide, shows no helical structures in water, and forms few helices even on the addition of TFE. The role of the G-H helical hairpin in protein folding is also discussed.

The backbone and tryptophan side-chain dynamics of thereduced and oxidized form of Escherichia coli thioredoxin were examined. The aim was to find out whether the changes in dynamics of the reduced and oxidizedthioredoxin permits access by the reduced form to structural states which are not available to the oxidized form. These differences lead to different effectson other thioredoxin activities such as induction of viral DNA polymerase and exonuclease. The results showed differences in dynamic mobility in the between the backbone regions of the two thioredoxin forms. The functional implications of these differences were discussed.

Immunogenic peptides of the dominant antigenic region in the transmembrane protein of simian immunodeficiency virus (SIV) possess preferences for water solution conformations other than the extended chain form configuration typical of random coil peptides. This was indicated by conformational studies using nuclear magnetic resonance on two synthetic peptides which correspond to the N- and C- terminal halves of the SIV of macaque origin.

The NMR structure of the full-length tumor suppressor p53 transactivation domain (TAD) in complex with the nuclear coactivator binding domain (NCBD) of key cellular proteins CBP is reported. The results suggested that a salt bridge between D49 of p53 and R2105 of NCBD might contribute to the binding specificity of the two subdomain AD1 and AD2 motifs of p53 to a target protein.

A study was conducted to examine the dynamics of the pathogenic mutants (P101L and H186R), protective mutants (Q167R and Q218K), and wild-type mouse PrP(89?230) at pH 5.5 and 3.5. Findings suggested the possibility that the pathogenic or dominant negative mutations exert their effects on non-native intermediate.

The article studies the functional dynamics of the folded ankyrin repeat domain (ARD) of I[kappa]B[alpha] using nuclear magnetic resonance (NME). Findings reveal that fifth and sixth repeats are only partially folded in the absence of nuclear factor [kappa]B.

An ensemble approach to the boundary element method that accurately predicts rotational tumbling time ([tau]c) for well-structured and rigid proteins by introducing two layers of molecular surfaces whose correlated velocities decay exponentially with distance is presented. The reliable prediction obtained by ([tau]c would help to detect intra- and intermolecular interactions and conformational switches between more ordered and less ordered states of the disordered segments.

The isothermal titration calorimetry and NMR spectroscopy were utilized to map the interaction between the transactivation domain (TAD) of p53 and the transcriptional coactivators CBP KIX domain. The KIX-binding affinity of p53 TAD was observed to be enhanced by simultaneous phosphorylation of Thr18 and Ser20.

NMR of [super 15]N-labeled Sm11 (104 residues) and a truncated variant (residues 50-104) are used to characterize the molecular properties of Sm11, a small ribonucleotide reductase (RNR) regulatory protein found in Saccharomyces cerevisiae. The findings from the study provide insight into Sm11 binding and inhibition of RNR and the manipulation of the potential regulation of eukaryotic RNR.

The microsecond and millisecond protein dynamics under a more extensive array of temperature and pH conditions were measured to explore the energy landscape of in the Escherichia coli dihydrofolate reductase ternary complex (E.THF.[NADP.sup.+]). The experimental results showed that physical changes within the energy landscape of the product ternary complex are tightly linked to maximum rates of hydride transfer.

The distinctive difference in structure and dynamics of the free and bound forms of the p160 steroid receptor coactivator ACTR and transcriptional coactivators CBP domains is described. The ACTR/CBP complex formation involves a synergistic mutual folding process in which the large conformational entropy cost is not compensated by increased mobility of the backbone in the complex.

Multiple time-scale dynamics of enzymes in different phases of the catalytic cycle were studied with the help of NMR relaxation techniques. An outline is presented on how protein dynamics affects events throughout the catalytic cycle, including substrate binding, chemical transformation and product release.

Bacterially expressed recombinant somatomedin B (rSMB) can be refolded to a single form that shows maximal activity in binding to plasminogen activator inhibitor-1 (PAI-1) and to a conformation-dependent monoclonal antibody (mAb 153). The NMR analysis shows that the stably refolded rSMB is identical to the material used for the solution structure determination and that it binds specifically to mAb 153 via an interface that includes the three aromatic side chains.

The structure and membrane-interaction properties of the peptide containing 30 amino acid residues derived from the mouse Doppel (Dp1) protein (mDp1(1-30)) are investigated. The results show a possible channel formation mechanism for the unprocessed Dpl protein that might be related to toxicity through direct cell membrane interaction and damage.

Dihydrofolate reductase (DHFR) has flexible active site loops facilitating ligand binding and catalysis. The role of side chain dynamics in ligand binding and loop conformation, methyl deuterium relaxation rates of Escherichia coli DHFR in binary folate and ternary folate is identified.

Research has been conducted on ubiquitously expressed nuclear protein ALY which is involved in mRNA export from the nucleus to cytoplasm. The authors have investigated the structure of ALY's conserved RNA binding domain, and they report that this structure explains the interaction nature of the multifuntional proteins.