Premium
Bacillus subtilis levansucrase: amino acid substitutions at one site affect secretion efficiency and refolding kinetics mediated by metals
Author(s) -
PetitGlatron M. F.,
Monteil I.,
Benyahia F.,
Chambert R.
Publication year - 1990
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1990.tb00566.x
Subject(s) - levansucrase , bacillus subtilis , secretion , biology , folding (dsp implementation) , amino acid , secretory protein , kinetics , biochemistry , protein folding , metal , metal ions in aqueous solution , mutant , biophysics , bacteria , chemistry , genetics , organic chemistry , physics , quantum mechanics , gene , electrical engineering , engineering
Summary Studies of the equilibrium between native and denatured forms of wild‐type levansucrase showed that the denatured form was predominant at 37°C and pH 7 in the absence of free metal. The shift to the native form was promoted by metal ions such as Fe 3+ or Ca 2+ . This metal‐dependent refolding process was not observed in levansucrase variants bearing the amino acid substitution Gly‐366→Asp or Gly‐366→Val. These variants were only slightly secreted by Bacillus subtilis although their signal sequences were normally cleaved and their exocellular forms stable. In contrast, the Gly‐366→Ser variant was secreted at near‐normal levels and shared a part of the in vitro refolding properties of the wild‐type protein. These differential properties might be related to the ability of the altered region to form a β‐turn structure. We discuss the possible role of metal ions in the coupling of protein folding and secretion.