Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 104, Issue 28, Pages 11670-11675Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.0704692104
Keywords
chaperone; protein folding; directed evolution
Categories
Ask authors/readers for more resources
It is often difficult to determine which of the sequence and structural differences between divergent members of multigene families are functionally important. Here we use a laboratory evolution approach to determine functionally important structural differences between two distantly related disulfide isomerases, DsbC and DsbG from Escherichia coli. Surprisingly, we found single amino acid substitutions in DsbG that were able to complement dsbC in vivo and have more DsbC-Iike isomerase activity in vitro. Crystal structures of the three strongest point mutants, DsbG K113E, DsbG V216M, and DsbG T200M, reveal changes in highly surface-exposed regions that cause DsbG to more closely resemble the distantly related DsbC. In this case, laboratory evolution appears to have taken a direct route to allow one protein family member to complement another, with single substitutions apparently bypassing much of the need for multiple changes that took place over approximate to 0.5 billion years of evolution. Our findings suggest that, for these two proteins at least, regions important in determining functional differences may represent only a tiny fraction of the overall protein structure.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available