Predominantly buried residues in the response regulator Spo0F influence specific sensor kinase recognition

Several alanine mutations in the response regulator Spo0F induce hypersporulation in Bacillus subtilis. L66A, I90A and H101A mutants are purported to be involved in contacts stabilizing the orientation of the alpha 4-helix and hence the beta 4-alpha 4 kinase recognition loop. Y13A is thought to affect the orientation of the alpha 1-helix and consequently phosphatase action. Using comparative NMR chemical shift analyses for these mutants, we have confirmed these suppositions and isolated residues in Spo0F critical in sensor kinases discrimination. In addition, we discuss how buried residues and intra-protein communication networks contribute to precise molecular recognition by ensuring that the correct surface is presented. (c) 2007 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.