2N7J

Sidechain chi1 distribution in B3 domain of protein G from extensive sets of residual dipolar couplings

2N7J の概要

• エントリーDOI: 10.2210/pdb2n7j/pdb
• 関連するPDBエントリー: 2OED
• NMR情報: BMRB: 25807
• 分子名称: Immunoglobulin G-binding protein G (1 entity in total)
• 機能のキーワード: signaling protein
• 由来する生物種: Streptococcus sp. 'group G'
• 細胞内の位置: Secreted, cell wall ; Peptidoglycan-anchor : P06654
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 6214.85

構造登録者

Grishaev, A.,Li, F.,Ying, J.,Bax, A. (登録日: 2015-09-12, 公開日: 2015-10-14, 最終更新日: 2024-05-01)

主引用文献

Li, F.,Grishaev, A.,Ying, J.,Bax, A.
Side Chain Conformational Distributions of a Small Protein Derived from Model-Free Analysis of a Large Set of Residual Dipolar Couplings.
J.Am.Chem.Soc., 137:14798-14811, 2015

PubMed Abstract: Accurate quantitative measurement of structural dispersion in proteins remains a prime challenge to both X-ray crystallography and NMR spectroscopy. Here we use a model-free approach based on measurement of many residual dipolar couplings (RDCs) in differentially orienting aqueous liquid crystalline solutions to obtain the side chain χ1 distribution sampled by each residue in solution. Applied to the small well-ordered model protein GB3, our approach reveals that the RDC data are compatible with a single narrow distribution of side chain χ1 angles for only about 40% of the residues. For more than half of the residues, populations greater than 10% for a second rotamer are observed, and four residues require sampling of three rotameric states to fit the RDC data. In virtually all cases, sampled χ1 values are found to center closely around ideal g(-), g(+) and t rotameric angles, even though no rotamer restraint is used when deriving the sampled angles. The root-mean-square difference between experimental (3)JHαHβ couplings and those predicted by the Haasnoot-parametrized, motion-adjusted Karplus equation reduces from 2.05 to 0.75 Hz when using the new rotamer analysis instead of the 1.1-Å X-ray structure as input for the dihedral angles. A comparison between observed and predicted (3)JHαHβ values suggests that the root-mean-square amplitude of χ1 angle fluctuations within a given rotamer well is ca. 20°. The quantitatively defined side chain rotamer equilibria obtained from our study set new benchmarks for evaluating improved molecular dynamics force fields, and also will enable further development of quantitative relations between side chain chemical shift and structure.

PubMed: 26523828
DOI: 10.1021/jacs.5b10072

実験手法

SOLUTION NMR