Regulation of the Dha operon of Lactococcus lactis: a deviation from the rule followed by the Tetr family of transcription regulators.
- Christen S Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
- Srinivas A
- Bähler P
- Zeller A
- Pridmore D
- Bieniossek C
- Baumann U
- Erni B
- 2006-06-09
Published in:
- The Journal of biological chemistry. - 2006
Amino Acid Sequence
Deoxyribonuclease I
Histidine
Lactococcus lactis
Models, Genetic
Molecular Sequence Data
Operon
Phosphotransferases (Alcohol Group Acceptor)
Promoter Regions, Genetic
Protein Binding
Protein Conformation
Repressor Proteins
Sequence Homology, Amino Acid
Transcription, Genetic
English
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.
- Language
-
- English
- Open access status
- bronze
- Identifiers
-
- DOI 10.1074/jbc.M603486200
- PMID 16760471
- Persistent URL
- https://sonar.ch/global/documents/1145
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