3hyi

Publication Abstract from PubMed

Proteins of the DUF199 family, present in all Gram-positive bacteria and best characterized by the WhiA sporulation control factor in Streptomyces coelicolor, are thought to act as genetic regulators. The crystal structure of the DUF199/WhiA protein from Thermatoga maritima demonstrates that these proteins possess a bipartite structure, in which a degenerate N-terminal LAGLIDADG homing endonuclease (LHE) scaffold is tethered to a C-terminal helix-turn-helix (HTH) domain. The LHE domain has lost those residues critical for metal binding and catalysis, and also displays an extensively altered DNA-binding surface as compared with homing endonucleases. The HTH domain most closely resembles related regions of several bacterial sigma70 factors that bind the -35 regions of bacterial promoters. The structure illustrates how an invasive element might be transformed during evolution into a larger assemblage of protein folds that can participate in the regulation of a complex biological pathway.

The structure of a bacterial DUF199/WhiA protein: domestication of an invasive endonuclease.,Kaiser BK, Clifton MC, Shen BW, Stoddard BL Structure. 2009 Oct 14;17(10):1368-76. PMID:19836336^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.