2iu6
REGULATION OF THE DHA OPERON OF LACTOCOCCUS LACTIS
Structural highlights
FunctionDHAQ_LACLA Coactivator for the transcription factor DhaS. The heterotetramer formed by DhaQ and DhaS functions as transcriptional regulator. Activated by covalent binding of dihydroxyacetone to DhaQ. The complex activates the dhaKLM operon.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedDihydroxyacetone (Dha) kinases are a novel family of kinases with signaling and metabolic functions. Here we report the x-ray structures of the transcriptional activator DhaS and the coactivator DhaQ and characterize their function. DhaQ is a paralog of the Dha binding Dha kinase subunit; DhaS belongs to the family of TetR repressors although, unlike all known members of this family, it is a transcriptional activator. DhaQ and DhaS form a stable complex that in the presence of Dha activates transcription of the Lactococcus lactis dha operon. Dha covalently binds to DhaQ through a hemiaminal bond with a histidine and thereby induces a conformational change, which is propagated to the surface via a cantilever-like structure. DhaS binding protects an inverted repeat whose sequence is GGACACATN6ATTTGTCC and renders two GC base pairs of the operator DNA hypersensitive to DNase I cleavage. The proximal half-site of the inverted repeat partially overlaps with the predicted -35 consensus sequence of the dha promoter. Regulation of the Dha operon of Lactococcus lactis: a deviation from the rule followed by the Tetr family of transcription regulators.,Christen S, Srinivas A, Bahler P, Zeller A, Pridmore D, Bieniossek C, Baumann U, Erni B J Biol Chem. 2006 Aug 11;281(32):23129-37. Epub 2006 Jun 7. PMID:16760471[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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