RAMACHANDRAN PLOT POLYGLYCINE
Louis, MO and used as received. Methods Protein Struct Stab Anal. Oligoglycines longer than 5 residues are normally insoluble in water. Structure, Function, and Genetics. To gain insight into the conformational preferences of the long polygly chains in solution we compared the UVRR spectra of polygly in 1. Experimental data on the conformational preferences of gly-based peptides in solution are very limited. Conformation of polygly and oligogly in solution.
Views Read Edit View history. This preference of the polygly backbone for the PGII conformation in solution is likely a result of favorable interactions between carbonyl dipoles in these extended helices. Solid samples For the amide region, we used pre-resonance nm excitation to minimize sample photodegradation. Ho and Brasseur 30 analyzed the Ramachandran plot of polygly in detail and also calculated electrostatic interactions. These conformations can be obtained by precipitation from solution. Discussion Polygly is the most flexible polypeptide because its lack of side chains removes steric hindrances.
The four figures below show the datapoints from a large set of high-resolution structures and contours for favored and for p,ot conformational regions for the general case all amino acids except Gly, Pro, and pre-Profor Gly, and for Pro. We compare the spectra of polygly in solution to known solid state structures.
Now, many decades later, there are tens of thousands of high-resolution protein structures determined polyglyvine X-ray crystallography and deposited in the Protein Data Bank PDB. The residue preceding proline “pre-proline” also has limited combinations compared to the general case. The polygly Ramachandran plot shows more allowed regions than for any other amino acid. Scattered light was collected using a back-scattering geometry, dispersed by a single monochromator and detected using a Princeton Instruments Spec Bull Chem Soc Jpn.
They showed that the energy minima in the carbonyl dipole-dipole interaction map correspond to regions populated by 3 1 -helix conformations left and right-handed in the Ramachandran map Fig.
Ramachandran plot – Wikipedia
Biochemistry methods Plots graphics. Balasubramanian D, Shaikh R. Abe Y, Krimm S.
Although polygly chains in solution show a preference for PGII conformations, they still maintain significant conformational freedom which is apparent from the increased solution bandwidths of the conformationally sensitive amide and CH 2 stretching bands. The third harmonic of a Nd: The spectra are arbitrarily scaled.
Raman studies of Solution Polyglycine Conformations
Our data indicate that long polygly chains —as well as the central residues of the gly 5 and gly 6 in solution assume an extended helix PGII-like or 3 1 -helix conformation. This downshift is likely due to weakening of the ramachanfran bonding between the peptide bond N-H and water, probably due to N-H dehydration.
Lithium salts increase the solubility of polygly.
These conformations can be obtained by precipitation from solution. Either case is usually shown against outlines for the theoretically favored regions. These amide bands result from polypeptide backbone atom stretching and bending vibrations which makes them sensitive and convenient markers for peptide and protein secondary structure. Polyglycine polygly is an important model system for understanding the structural preferences of unfolded polypeptides in solution.
Conclusions We utilized UV resonance Raman and visible Raman spectroscopy to investigate the conformation of the most flexible polypeptide, polygly in aqueous solution. See also PDB for a list of similar software. Discussion Polygly is the most flexible polypeptide because its lack of side chains removes steric hindrances.
This result implies that long polygly chains and the central parts of polyglyxine short oligogly chains populate the same conformational space in aqueous solution. National Center for Biotechnology PolyylycineU. Recently we showed that spectrum of gly 3 closely approximates the spectrum of the two terminal peptide bonds in longer polygly, and that the total UVRR of the oligogly in solution can be treated as a linear sum of the comprising peptide bonds.
A nm holographic notch filter Kaiser Optical Systems Inc. In other projects Wikimedia Commons. The spectra of polygly in solution ramacyandran solid polygly in the PGII form are essentially identical. Biochim Biophys Acta, Proteins Proteomics. See other articles in PMC that cite the published article.
Retrieved from ” https: We utilized UV resonance Raman and visible Raman spectroscopy to investigate the conformation of polyg,ycine most flexible polypeptide, polygly in aqueous solution. Bosco Ho for permission to use a figure from his publication. Figure 3 compares the Raman spectra of the CH 2 stretches of polygly in solution and solid state.
Acta Crystallogr, Sect B: