Donato G M, Kawula T H
Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7290, USA.
J Biol Chem. 1998 Sep 11;273(37):24030-6. doi: 10.1074/jbc.273.37.24030.
H-NS is an Escherichia coli nucleoid protein known only to function as a modulator of gene expression. In this study, we found that specific single amino acid substitutions in H-NS caused an approximately 50% increase in flagellum rotational speed. In fluorescence anisotropy and chemical cross-linking assays, H-NS interacted with the flagellar torque-generating rotor protein FliG to form a complex with a Kd of 2.15 microM. Furthermore, one of the altered H-NS proteins that exhibited high speed flagellum rotation bound FliG 50% tighter than wild-type H-NS. These results demonstrate the first non-regulatory role for H-NS and provide a direct correlation between H-NS-FliG binding affinities, flagellar rotation, and motor torque generation.
