2fxy
Solution structure of 55-72 segment of staphylococcal nuclease
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OverviewOverview
Two synthetic peptides, SNasealpha1 and SNasealpha2, corresponding to, residues G55-I72 and K97-A109, respectively, of staphylococcal nuclease, (SNase), are adopted for detecting the role of helix alpha1 (E57-A69) and, helix alpha2 (M98-Q106) in the initiation of folding of SNase. The, helix-forming tendencies of the two SNase peptide fragments are, investigated using circular dichroism (CD) and two-dimensional (2D), nuclear magnetic resonance (NMR) methods in water and 40% trifluoroethanol, (TFE) solutions. The coil-helix conformational transitions of the two, peptides in the TFE-H2O mixture are different from each other. SNasealpha1, adopts a low population of localized helical conformation in water, and, shows a gradual transition to helical conformation with increasing, concentrations of TFE. SNasealpha2 is essentially unstructured in water, but undergoes a cooperative transition to a predominantly helical, conformation at high TFE concentrations. Using the NMR data obtained in, the presence of 40% TFE, an ensemble of alpha-helical structures has been, calculated for both peptides in the absence of tertiary interactions., Analysis of all the experimental data available indicates that formation, of ordered alpha-helical structures in the segments E57-A69 and M98-Q106, of SNase may require nonlocal interactions through transient contact with, hydrophobic residues in other parts of the protein to stabilize the, helical conformations in the folding. The folding of helix alpha1 is, supposed to be effective in initiating protein folding. The formation of, helix alpha2 depends strongly on the hydrophobic environment created in, the protein folding, and is more important in the stabilization of the, tertiary conformation of SNase.
About this StructureAbout this Structure
2FXY is a Single protein structure of sequence from [1]. Active as Micrococcal nuclease, with EC number 3.1.31.1 Full crystallographic information is available from OCA.
ReferenceReference
Two peptide fragments G55-I72 and K97-A109 from staphylococcal nuclease exhibit different behaviors in conformational preferences for helix formation., Wang M, Shan L, Wang J, Biopolymers. 2006 Oct 15;83(3):268-79. PMID:16767771
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