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Detection of a hidden folding intermediate in the focal adhesion target domain: Implications for its function and folding
Author(s) -
Zhou Zheng,
Feng Hanqiao,
Bai Yawen
Publication year - 2006
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.21107
Subject(s) - folding (dsp implementation) , biophysics , protein folding , chemistry , focal adhesion , downhill folding , helix (gastropod) , domain (mathematical analysis) , function (biology) , native state , helix bundle , phi value analysis , crystallography , microbiology and biotechnology , protein structure , biochemistry , biology , signal transduction , ecology , mathematical analysis , mathematics , electrical engineering , snail , engineering
The focal adhesion target (FAT) domain of focal adhesion kinase has a four‐helix bundle structure. Based on a hydrogen exchange‐constrained computer simulation study and some indirect experimental results, it has been suggested that a partially unfolded state of the FAT domain with the N‐terminal helix unfolded plays an important role in its biological function. Here, using a native‐state hydrogen exchange method, we directly detected an intermediate with the N‐terminal helix unfolded in a mutant (Y925E) of the FAT domain. In addition, kinetic folding studies on the FAT domain suggest that this intermediate exists on the native side of the rate‐limiting transition state for folding. These results provide more direct evidence of the existence of the proposed intermediate and help to understand the folding mechanism of small single domain proteins. Proteins 2006. © 2006 Wiley‐Liss, Inc.