Gw. Daughdrill et al., THE C-TERMINAL HALF OF THE ANTI-SIGMA FACTOR, FLGM, BECOMES STRUCTURED WHEN BOUND TO ITS TARGET, SIGMA(28), Nature structural biology, 4(4), 1997, pp. 285-291
The interaction between the flagellum specific sigma factor, sigma(28)
, and its inhibitor, FlgM, was examined using multidimensional heteron
uclear NMR. Here we observe that free FlgM is mostly unfolded, but abo
ut 50% of the residues become structured when bound to sigma(28). Our
analysis suggests that the sigma(28) binding domain of FlgM is contain
ed within the last 57 amino acids of the protein while the first 40 am
ino acids are unstructured in both the free and bound states. Genetic
analysis of flgM mutants that fail to inhibit sigma(28) activity revea
l amino acid changes that are also isolated to the C-terminal 57 resid
ues of FlgM. We postulate that the lack of structure in free and bound
FlgM is important to its role as an exported protein.