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Isolation, characterization and structure of subtilisin from a thermostable Bacillus subtilis isolate
Author(s) -
Mustafa Kamal,
JanOlov Höög,
Rudolf Kaiser,
Jawed Shafqat,
Tashmeem Razzaki,
Zafar H. Zaidi,
Hans Jörnvall
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01145-5
Subject(s) - subtilisin , thermostability , bacillus subtilis , serine protease , biochemistry , protease , thermophile , strain (injury) , bacillaceae , peptide sequence , bacillales , serine , amino acid , biology , enzyme , chemistry , bacteria , genetics , gene , anatomy
A serine protease has been isolated and characterized from Bacillus subtilis , strain RT‐5 (a thermostable soil isolate from the Tharparkar desert of Pakistan) able to grow at 55°C. The primary structure was established by a combination of protein and DNA‐sequence analyses. The amino‐acid sequence, inhibition pattern and solubility properties identify the enzyme as a subtilisin. It has 43 amino‐acid replacements toward subtilisin BPN′ and as much as 83 replacements toward another subtilisin, confirming that strain variabilities are extensive between different subtilisin forms. However, the structure is identical to one of unknown functional properties deduced from DNA and is closely related to mesentericopeptidase but that homologue is not thermostable. From comparisons with that form and with subtilisin BPN′, it is concluded that replacements of Ala → Ser at positions 85 and 89, Ser → Ala at position 88 and Asp or Ser → Asn at position 259 may promote thermostability.