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Repacking of hydrophobic residues in a stable mutant of apocytochrome b 562 selected by phage‐display and proteolysis
Author(s) -
Feng Hanqiao,
Bai Yawen
Publication year - 2004
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.20161
Subject(s) - proteolysis , hydrophobic effect , mutant , sequence (biology) , chemistry , crystallography , stereochemistry , biochemistry , biophysics , biology , enzyme , gene
To test a hydrophobic core‐directed protein design approach, we previously have used phage‐display and proteolysis to select stably folded proteins from a library of mutants of apocytochrome b 562 . The consensus sequence of the selected mutants has hydrophilic residues at two of the three positions that are designed to form a hydrophobic core. To understand this unexpected result, we determined the high‐resolution structure of one of the selected mutants using multi‐dimensional nuclear magnetic resonance (NMR). The structure shows that the two hydrophilic residues in the consensus sequence were on the surface of the structure. Instead, two of their neighboring hydrophobic residues reorganized their side‐chain conformations and formed the hydrophobic core. This result suggests that the hydrophobic core‐directed protein design by phage‐display and proteolysis is a valid method in general but alternative hydrophobic packing needs to be considered in the initial design. The unexpected repacking of the hydrophobic residues also highlights the plastic nature of protein structures. Proteins 2004. © 2004 Wiley‐Liss, Inc.