%0 Journal Article
%T Solution structure and backbone dynamics of human Raf-1 kinase inhibitor protein.
%A Guo C
%A Yi C
%A Peng Y
%A Wen Y
%A Lin D
%J Biochem Biophys Res Commun
%V 438
%N 1
%D Aug 2013 16
%M 23872143
%F 3.322
%R 10.1016/j.bbrc.2013.07.039
%X Human Raf-1 kinase inhibitor protein (hRKIP) is a small multi-functional protein of 187 residues. It contains a conserved pocket, which binds a wide range of ligands from various small molecules to distinct proteins. To provide a structural basis for the ligand diversity of RKIP, we herein determined the solution structure of hRKIP, and analyzed its structural dynamics. In solution, hRKIP mainly comprises two antiparallel β sheets, two α helices and two 3₁₀ helices. NMR dynamic analysis reveals that the overall structure of hRKIP is rigid, but its C-terminal helix which is close to the ligand-binding site is mobile. In addition, residues around the ligand-binding pocket exhibit significant conformational exchange on the μs-ms timescale. Conformational flexibility may allow the ligand-binding pocket and the C-terminal helix to adopt various conformations to interact with different substrates. This work may shed light on the underlying molecular mechanisms of how hRKIP recognizes and binds diverse substrate ligands.