Directed evolution to re-adapt a co-evolved network within an enzyme.

ABSTRACT: We have previously used targeted active-site saturation mutagenesis to identify a number of transketolase single mutants that improved activity towards either glycolaldehyde (GA), or the non-natural substrate propionaldehyde (PA). Here, all attempts to recombine the singles into double mutants led to unexpected losses of specific activity towards both substrates. A typical trade-off occurred between soluble expression levels and specific activity for all single mutants, but many double mutants decreased both properties more severely suggesting a critical loss of protein stability or native folding. Statistical coupling analysis (SCA) of a large multiple sequence alignment revealed a network of nine co-evolved residues that affected all but one double mutant. Such networks maintain importan

SUBMITTER: Strafford J 

PROVIDER: S-EPMC3657141 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature