Engineering of a cold-adapted protease by sequential random mutagenesis and a screening system

Article Abstract:

A study was conducted describing the successful isolation of a cold-adapted protease subtilisin by evolutionary engineering based on sequential in vitro random mutagenesis. The technique enabled the researchers to obtain a cold-adapted mutant subtilisin, named m-63, with proteolytic activity 100% higher than that of the wild type at 10 degrees C. The negative mutation for proteolytic activity, V72I, was located in the internal alpha-helical structure. Analysis suggested that the V72I mutant is very fragile even at 10 degrees C.

Proteases, Mutation (Biology), Mutation

Molecular characterization of a gene encoding extracellular serine protease isolated from a subtilisin inhibitor-deficient mutant of Streptomyces albogriseolus S-3253

Article Abstract:

Standard procedures help isolate an extracellular chymotrypsin-type protease, SAM-P20, from a mutant of Streptomyces albogriseolus S-3253, which does not produce Streptomyces subtilisn inhibitor. Gene cloning and sequencing of the protease reveals the homology between the amino acid sequence of the amino-terminal region of SAM-P20 and the sequences of Streptomyces griseus proteases A and B. Experimental studies reveal the expression and secretion of the cloned SAM-P20 in E. coli JM109.

Analysis, Streptomyces, Microbial enzymes, Microbial mutation

Functional mapping of amino acid residues responsible for the antibacterial action of apidaecin

Article Abstract:

The C-terminal region, and proline and arginine amino acids are responsible for the antibacterial activity of the peptide apidaecin (AP). All the mutations in the group three mutants with the least AP1 gene activity are localized in the C-terminal. The direct production of AP1 mediated by the OmpA signal sequence, shows the same growth inhibition pattern in each mutant AP1 as shown by the Streptomyces subtilisin inhibitor-AP1 fusion protein.

Antibacterial agents, Peptides, Structure-activity relationships (Pharmacology)