Premium
Modular structure of Fix J: homology of the transcriptional activator domain with the ‐35 binding domain of sigma factors
Author(s) -
Kahn D.,
Ditta G.
Publication year - 1991
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1991.tb00774.x
Subject(s) - biology , homology (biology) , activator (genetics) , transcription (linguistics) , gene , promoter , genetics , transcriptional regulation , rhizobium , regulator , sigma factor , microbiology and biotechnology , transcription factor , computational biology , gene expression , linguistics , philosophy
Summary The FixL/Fix J two‐component system is a global regulator of nitrogen‐fixation genes in Rhizobium meliloti. The transcriptional activator FixJ contains two modules: its N ‐terminal module is homologous with other two‐component regulators; its C ‐terminal module shows homology with various transcriptional activators, and with the C ‐terminal region of σ factors, which is involved in the discrimination of the ‐35 region of bacterial promoters. We show that C ‐terminal module of Fix J contains the entire transcription activation function, and that the N ‐terminal module regulates this activity negatively. Oligonucleotide directed mutagenesis of the transcriptional activator module demonstrated the importance of a potential helix‐turn‐helix structure.