1q80
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(New page: 200px<br /><applet load="1q80" size="450" color="white" frame="true" align="right" spinBox="true" caption="1q80" /> '''Solution structure and dynamics of Nereis sa...)
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Revision as of 22:20, 20 November 2007
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Solution structure and dynamics of Nereis sarcoplasmic calcium binding protein
Overview
The solution structure of Nereis diversicolor sarcoplasmic calcium-binding, protein (NSCP) in the calcium-bound form was determined by NMR, spectroscopy, distance geometry and simulated annealing. Based on 1859 NOE, restraints and 262 angular restraints, 17 structures were generated with a, rmsd of 0.87 A from the mean structure. The solution structure, which is, highly similar to the structure obtained by X-ray crystallography, includes two open EF-hand domains, which are in close contact through, their hydrophobic surfaces. The internal dynamics of the protein backbone, were determined by studying amide hydrogen/deuterium exchange rates and, 15N nuclear relaxation. The two methods revealed a highly compact and, rigid structure, with greatly restricted mobility at the two termini. For, most of the amide protons, the free energy of exchange-compatible, structural opening is similar to the free energy of structural stability, suggesting that isotope exchange of these protons takes place through, global unfolding of the protein. Enhanced conformational flexibility was, noted in the unoccupied Ca2+-binding site II, as well as the neighbouring, helices. Analysis of the experimental nuclear relaxation and the molecular, dynamics simulations give very similar profiles for the backbone, generalized order parameter (S2), a parameter related to the amplitude of, fast (picosecond to nanosecond) movements of N(H)-H vectors. We also noted, a significant correlation between this parameter, the exchange rate, and, the crystallographic B factor along the sequence.
About this Structure
1Q80 is a Single protein structure of sequence from Neanthes diversicolor. Full crystallographic information is available from OCA.
Reference
Solution structure and internal dynamics of NSCP, a compact calcium-binding protein., Rabah G, Popescu R, Cox JA, Engelborghs Y, Craescu CT, FEBS J. 2005 Apr;272(8):2022-36. PMID:15819893
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