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Researchers have investigated all the amino acid residues of the human c-Ha-Ras protein in terms of conformational differences between the inactive and active forms. This involved applying uniform 13C/15N-labeling and triple-resonance NMR techniques. It was found to be a characteristic feature of the GTP-bound form of Ras that the L1, L2 and L4 loop regions are in a fairly slow interconversion between two or more stable conformers. It is possible that GAPs, the negative regulators, bind to the polysteric binding interface of Ras and cooperatively choose a conformer which can undertake transition of the GTPase catalytic centre.

The conformational rigidity of 5-methylaminomethyluridine ((mnm)(super 5)U) depends on the 5'-phosphate group. The interactions between the 5-methylaminomethyl and 5'-phosphate groups of (pmnm)(super 5)U limit the conformation about the glycosidic bond to a low anti form. The interaction increases steric repulsion between 2-carbonyl and 2'-hydroxyl groups in the C2'-endo form. The first position of the anticodon of Escherichia coli tRNA(sub 4)(super Arg) for codons AGA/AGG contains (mnm)(super 5)U. A study on conformational analysis uses NMR spectra and molecular dynamics.

Replacement of the unique Phe residue of (Phe 23) human epidermal growth factor (hEGF) with various unnatural phenylalanine analogs such as 3-azaphenylalanine (3aF), 2-azaphenylalanine (2aF), 4-flurophenylalanine (4fF) and 4-azaphenylalanine (4aF) aid the study of receptor binding of Phe 23 hEGF. Comparison of the receptor binding affinities of Phe 23 hEGF with that of the variants reveals that replacement of Phe 23 with 4fF and 4aF decreases the affinity and replacement, while 3aF and 2aF increase the affinity.

Structural and NMR spectroscopic analysis of glycoproteins containing KDN reveal the presence of KDN residues in N-linked glycan units. The N-linked glycan chains consist of bi and triantennary complex-type units of KDN-glycoproteins isolated from rainbow trout vitelline envelopes. Immunohistochemical methods reveal the localization of KDN units around the unfertilized egg's micropyle and the vitelline envelope's second layer. KDN-gp plays a role in sperm-egg fertilization.

Site-directed mutagenesis on c-Ha-Ras protein's effector region reveals that aromatic Tyr-32 residue lies within the Ras protein's guanosine-5' triphosphatase form. Tyr-32 exists on the surface of Ras protein's guanosine-5'-triphosphatase form, due to direct interaction with the target molecule. Ras residue Tyr-40 stabilizes the target molecule's interactive configuration.

A study was conducted on the secondary structure of the colicin E3 immunity protein using two-dimensional nuclear magnetic resonance spectroscopy. Homonuclear methods were used to analyze the fingerprint region of the spectrum while heteronuclear methods were used to identify overlapping resonances and led to the complete 1H and 15N resonance assignments. The results show that the E3 immunity protein includes a four-stranded antiparallel beta-sheet.

A heteronuclear-nuclear magnetic resonance spectroscopy was used to solve the solution structure of the murine T cell intracellular antigen-1 RNA recognition motifs (TIA-1 RRM2). The similarities observed between the RNA-binding modes of the TIA-1 RRM2 and the U2AF65 RRM2 provides better understanding of the RNA recognition manner of TIA-1.

Discusses the results of a proton nuclear magnetic resonance study of the trimannosyl unit in a pentaantennary decasaccharide structure. Chemical shifts of all the ring protons; Complete assignment of the proton resonances and conformational characterization.