Biochemistry

Protein Waves

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Science  14 Oct 2005:
Vol. 310, Issue 5746, pp. 197
DOI: 10.1126/science.310.5746.197b

Molecular dynamics are essential to protein stability and function. Nuclear magnetic resonance methods can measure residual internuclear dipolar couplings, which report on the average orientations of internuclear vectors on the slow time scales that are important for many biological processes (up to milliseconds). Bouvignies et al. took an in-depth look at the dynamics of an immunoglobulin-binding domain of streptococcal protein G and identified a long-range network of correlated motions. In the β sheet, an alternating pattern of dynamics resembled a standing wave: Nodes were associated with strongly hydrophobic side chains buried in the core of the protein that probably anchor the backbone motions as they propagate across the β sheet. The motion was correlated across hydrogen bonds, suggesting that dynamic information is transmitted across hydrogen bond networks. Independent confirmation of the dynamic network was provided by hydrogen-bond scalar coupling analysis. The amplitude of motion increased across the sheet, so that the greatest flexibility was in the strand that interacts with the antigen-binding domain of immunoglobulin G. Similar processes of information transfer through hydrogen bond networks may be important in processes such as allosteric regulation. — VV

Proc. Natl. Acad. Sci. USA 102, 13885 (2005).

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