The global regulator H-NS binds to two distinct classes of sites within the TnlO transpososome to promote transposition

• Published in: Molecular microbiology Vol. 64; no. 4; p. 1000
• Main Authors: Ward, Chris M, Wardle, Simon J, Singh, Randeep K, Haniford, David B
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.05.2007
• Subjects: Bacterial proteins; Bacteriology; Binding sites; Biochemistry; Mutation
• ISSN: 0950-382X; 1365-2958

The histone-like nucleoid structuring protein (H-NS) is a global transcriptional regulator that influences stress response and virulence pathways in Gram-negative bacteria. H-NS also promotes Tn10 transposition by binding directly to the transpososome and inducing a conformational change in the transpososome that favours intermolecular transposition events. H-NS binds preferentially to curved DNA and can bend non-curved DNA, it self-oligomerizes and can interact with other proteins. To determine what functions of H-NS are important in promoting Tn 10 transposition, we have examined the ability of two mutant forms of H-NS, P11 6S and 1-64, to act in Tn10 transposition. We provide evidence that the initial interaction of H-NS with the transpososome is dependent on H-NS binding to a specific structure in DNA flanking the transposon end. Additional molecules of H-NS then bind within the transposon end. This latter event appears to be directed by H-NS binding to the TnlO transposase protein, and is important in maintaining the transpososome in a conformation that promotes intermolecular transposition. The binding of H-NS to a transposase protein is a novel function for this important regulatory molecule. [PUBLICATION ABSTRACT]