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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.

Research has been conducted on the blue copper proteins' electron self-exchange. The use of the general NMR method in determining the second-order rate constant for this electron self-exchange is described.

Mutational analysis indicate that insulin possessing a tertiary fold can express the biological activity provided the molecule is flexible and has the propensity to form the secondary structure as seen in the mutant insulin. This suggests that native insulin's compact secondary structure is not required for biological activity.

Nuclear magnetic resonance spectroscopic study was utilized to describe the solution structure and backbone dynamics of the human alpha3-chain type VI collagen. Results have shown that the global fold configuration retained its form in the solution phase and assumed the same form as in the crystal phase and C5 domain core. It was indicated that the additional six residues in the N-terminal and the 12 residues in the C-terminal affected the function of the C5 domain.

NMR spectroscopy and restrained molecular dynamics were utilized to provide detailed three-dimensional solution structures of the R6 human insulin hexamer. Data indicated a compact, rigid, symmetrical and almost crystalline solution structure of R6 hexamer which is shorter than the native R state. Furthermore, the phenylalanine residue on the B25 ring position has no effect on the configuration of the molecule.

Characterization of plastocyanin from Anabaena variabilis (A.v. PCu) by nuclear resonance spectroscopy showed that it shares structural similarities with plastocyanins previously characterized by X-ray diffraction and NMR techniques. However, one feature which makes it unique is the absence of the beta-turn which is found between residues 58 and 61 in other plastocyanins. Instead, an extension of the small helix and the formation of an appended loop from excess amino acid residues. Structure calculations are presented.

Two-dimensional NMR titration studies of the molecular properties such as hydrogen bonds, electrostatic interactions and pH-based structural modifications of Asp(B9) human insulin reveal that the Asp(B9) residue forms a B-chain alpha-helix N-cap through the helix dipole and side-chain carboxyl group interactions. All the salt bridges develop between Asn(A21) and Arg(B22) and between the Glu(B13) and His(B10) residues at an ionizing pH value. Asp(B9) is dimeric in nature and contains hydrogen bonds between the C-terminal carboxyl group of Thr(B30) residue and the amide proton of Val(A3).

A method for quantitative determination of amide proton exchange rates of the order of reciprocal hours is presented. The method, which makes use of the 2D nuclear magnetic resonance spectroscopy for recording of the exchange processes, is applied in the study of the 50-residue des-(Phe(B25)) mutant of human insulin. Results show that the exchange rates of the mutant insulins' amide protons have been successfully measured and experimental conditions exert an influence on the rate of proton exchanges.

A novel nuclear magnetic resonance method combining isotopic carbon labeling and spectral analysis was used to determine conformational alteration in the human somatotropin brought about by changes in hydronium ion concentration. Labeling of the carbonyl group of leucine residues allows for the observation of 26 different sites within the hormone. Isotopic carbon nuclear magnetic resonance spectroscopy can also be used to determine mechanisms involved during equilibrium folding.

An NMR approach to the measurement of the exchange rates of gradually exchanging amide protons in proteins is applied to the des-(Phe(B25)) mutant of human insulin. Fitting of a model involving exponential decay to the parameters yielded by a linear prediction analysis of one-dimensional free induction decays observed during the exchange of amide protons with solvent deuterium provided the exchange rates.

The solution structure of a fully active C-terminally cross-linked relaxin-like factor (RLF) analogue is compared with the native synthetic human RLF (hRLF) to understand the partial obliteration of the two essential RLF receptor-binding site residues, valine B19 and tryptophan B27. The results provide insight into the solution structure of the native hormone representing an inactive conformer and the existence of dynamic equilibrium between the C-terminally unfolded binding conformation and the inactive conformation of the RLF.

A combination of NMR relaxation measurements and chemical shift titrations is employed to explain the exchange dynamics, including the protonation, rotamerization and tatutomerization of His61 in plastocyanin from Anabaena variabilis. The approach is shown to be also helpful in studying the conformational exchange of histidine side chain.

The article discusses the kinetics, as well as the mechanism involved behind the acid transition of the active site in plastocyanin. The results show that the transition leads to a significant change in the redox potential of the protein.

An experiment was conducted to demonstrate that pseudocontact shifts induced by the paramagnetic [Ni.sup.2+] ion bound to the protein helps in obtaining the information about the structure of a native nonmetalloprotein. Also, it was shown that potential metal binding sites on the surface of a native nonmetalloprotein can be identified using the paramagnetic [Cu.sup.2+] ion as a probe.

The rapid long-range electron-transfer reactivity that characterizes blue copper proteins, such as plastocyanin, is detailed. It is experimentally verified by longitudinal paramagnetic NMR relaxation that the unpaired electron spin density of oxidized A.v. PCu is delocalized onto the ligands.

A detailed, quantitative characterization of conformational exchange processes in proteins, on the microsec-millisec time scale is presented. The approach allows a differentiation between two-site and multiple-site exchange processes and reveals that the protonation/deprotonation of histidine is at least a three-site exchange process.

Paramagnetic longitudinal proton relaxation can provide detailed information about short-lived, transient protein complexes where the intermolecular interactions are close to diffusion limit. The interaction is monitored by the intermolecular paramagnetic contribution to the longitudinal relaxation of protons at or close to the contact surface.