Download MendeleyRegulation 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.(2006) J Biol Chem 281: 23129
- PubMed: 16760471
- DOI: https://doi.org/10.1074/jbc.M603486200
- Primary Citation of Related Structures:
2IU4, 2IU5, 2IU6 - PubMed Abstract:
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.
Organizational Affiliation:
Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
