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Structure. 2009 Oct 14;17(10):1368-76. doi: 10.1016/j.str.2009.08.008.

The structure of a bacterial DUF199/WhiA protein: domestication of an invasive endonuclease.

Author information

1
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA 98006, USA.

Abstract

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.

PMID:
19836336
PMCID:
PMC2766575
DOI:
10.1016/j.str.2009.08.008
[Indexed for MEDLINE]
Free PMC Article

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