2iu4: Difference between revisions
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==Overview== | ==Overview== | ||
Dihydroxyacetone (Dha) kinases are a novel family of kinases with | Dihydroxyacetone (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. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:56:00 2008'' | ||
Revision as of 18:56, 21 February 2008
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DIHYDROXYACETONE KINASE OPERON CO-ACTIVATOR DHA-DHAQ
OverviewOverview
Dihydroxyacetone (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.
About this StructureAbout this Structure
2IU4 is a Single protein structure of sequence from Lactococcus lactis with and as ligands. Active as Glucokinase, with EC number 2.7.1.2 Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
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
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