Expression and activity analyses of industrially important extracellular enzymes produced by a bacilysin knock-out mutant of Bacillus Subtilis

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2018
Aytekin, Samet
Bacilysin, the smallest peptide antibiotic known to date, is produced non-ribosomally by Bacillus subtilis by the collective actions of seven proteins transcribed from bacABCDEF operon and bacG gene. Bacilysin is a two-amino acid peptide composed of L-alanine and a modified amino acid, L-anticapsin. Bacilysin biosynthesis was shown to be strongly regulated by quorum sensing through the actions of global regulator proteins including Spo0K, Spo0H, Spo0A, ComQ/ComX, ComP/ComA as well as several Phr proteins, OppA, CodY, SrfA and AbrB. Involvement of large numbers of regulatory proteins in bacilysin biosynthesis raises the question of whether the bacilysin itself affects physiological processes its own producer cells. Comparative secretome analysis between B. subtilis PY79 and its bac operon-silenced derivative OGU1, recently performed by our group, has identified more than 200 proteins differentially expressed in the mutant strain. Since B. subtilis is one of the most important cell-factories with a capacity to produce a wide range of extracellular enzymes, of biotechnological interest was a significant increment in levels of the industrially-important extracellular enzymes upon the disruption of bac operon. These enzymes included arabinanase, chitosanase, levanase, phytase, lipase, bacillopeptidase F, minor extracellular protease and endonuclease. This study aims to compare the expression profiles of the respective abn2, csn, sacC, phy, estA, bpr, vpr and YhcR genes as well as the enzymatic activities of their products between two strains. Both approaches showed a significant increase of these eight selected proteins in the OGU1 strain, suggesting a possible direct or indirect effect of the bacilysin on their biosynthesis.

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Citation Formats
S. Aytekin, “Expression and activity analyses of industrially important extracellular enzymes produced by a bacilysin knock-out mutant of Bacillus Subtilis,” M.S. - Master of Science, Middle East Technical University, 2018.