Core L J, Ishikawa S, Perego M
Division of Cellular Biology, Department of Molecular and Experimental Medicine, MEM-116, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Peptides. 2001 Oct;22(10):1549-53. doi: 10.1016/s0196-9781(01)00491-0.
In the Bacillus subtilis phosphorelay signal transduction system for sporulation initiation, signals competing with the differentiation process are interpreted by aspartyl-phosphate phosphatases that specifically dephosphorylate the Spo0F or Spo0A response regulators. The RapA phosphatase is regulated by the PhrA pentapeptide that directly and specifically inhibits its activity. PhrA specificity for RapA inhibition is dependent upon the amino acid sequence of the peptide. Here we show that the pentapeptide affinity for the phosphatase requires a free carboxylate group at the C-terminal amino acid. A free C-terminal carboxylic acid PhrA pentapeptide inhibits RapA phosphatase activity at a 1:1 ratio and it is approximately 200 fold more active than a C-terminal amide peptide. Therefore, coordination of the terminal carboxylate group appears to be critical for peptide binding to RapA.
在枯草芽孢杆菌中用于启动芽孢形成的磷酸化信号转导系统中，与分化过程竞争的信号由天冬氨酰 - 磷酸磷酸酶进行解读，这些磷酸酶能特异性地使Spo0F或Spo0A应答调节因子去磷酸化。RapA磷酸酶受PhrA五肽调节，PhrA五肽直接且特异性地抑制其活性。PhrA对RapA抑制的特异性取决于该肽的氨基酸序列。在此我们表明，五肽对磷酸酶的亲和力要求C末端氨基酸有一个游离的羧基。游离C末端羧酸的PhrA五肽以1:1的比例抑制RapA磷酸酶活性，其活性比C末端酰胺肽高约200倍。因此，末端羧基的配位似乎对肽与RapA的结合至关重要。
