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Fast and faster: A designed variant of the B‐domain of protein A folds in 3 μsec
Author(s) -
Arora Pooja,
Oas Terrence G.,
Myers Jeffrey K.
Publication year - 2004
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.03541304
Subject(s) - domain (mathematical analysis) , fold (higher order function) , computational biology , physics , biophysics , crystallography , biology , computer science , chemistry , mathematics , mathematical analysis , programming language
We have introduced the mutation glycine 29 to alanine, designed to increase the rate of protein folding, into the B‐domain of protein A (BdpA). From NMR lineshape analysis, we find the G29A mutation increases the folding rate constant by threefold; the folding time is 3 μsec. Although wild‐type BdpA folds extremely fast, simple‐point mutations can still speed up the folding; thus, the folding rate is not evolutionarily maximized. The short folding time of G29A BdpA (the shortest time yet reported) makes it an attractive candidate for an all‐atom molecular dynamics simulation that could potentially show a complete folding reaction starting from an extended chain. We also constructed a fluorescent variant of BdpA by mutating phenylalanine 13 to tryptophan, allowing fluorescence‐based time‐resolved temperature‐jump measurements. Temperature jumps and NMR complement each other, and give a very complete picture of the folding kinetics.