Abstract
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.
Publication types
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Amino Acid Substitution
-
Bacterial Proteins / chemistry
-
Bacterial Proteins / genetics
-
Bacterial Proteins / metabolism*
-
Cross-Linking Reagents
-
DNA-Binding Proteins / chemistry
-
DNA-Binding Proteins / genetics
-
DNA-Binding Proteins / metabolism*
-
Escherichia coli / genetics
-
Escherichia coli / physiology*
-
Escherichia coli / ultrastructure
-
Flagella / physiology*
-
Flagella / ultrastructure
-
Fluorescence Polarization
-
Kinetics
-
Microscopy, Electron, Scanning
-
Models, Structural
-
Movement
-
Recombinant Proteins / chemistry
-
Recombinant Proteins / metabolism
Substances
-
Bacterial Proteins
-
Cross-Linking Reagents
-
DNA-Binding Proteins
-
Flig protein, Bacteria
-
H-NS protein, bacteria
-
Recombinant Proteins