Reciprocal domain evolution within a transactivator in a restricted sequence space.

ABSTRACT: offhough the concept of domain merging and shuffling as a major force in protein evolution is well established, it has been difficult to demonstrate how domains coadapt. Here we show evidence of coevolution of the Sinorhizobium meliloti NifA (SmNifA) domains. We found that, because of the lack of a conserved glycine in its DNA-binding domain, this transactivator protein interacts weakly with the enhancers. This defect, however, was compensated by evolving a highly efficient activation domain that, contrasting to Bradyrhizobium japonicum NifA (BjNifA), can activate in trans. To explore paths that lead to this enhanced activity, we mutagenized BjNifA. After three cycles of mutagenesis and selection, a highly active derivative was obtained. Strikingly, all mutations changed to amino acids alr

SUBMITTER: Juarez K 

PROVIDER: S-EPMC16236 | biostudies-literature | 2000 Mar

REPOSITORIES: biostudies-literature