Journal of Microbiology

Research Support, Non-U.S. Gov'ts

Identification of Genes for Mycothiol Biosynthesis in Streptomyces coelicolor A3(2): Joo-Hong Park , Chang-Jun Cha , Jung-Hye Roe; J. Microbiol. 2006;44(1):121-125.; DOI: https://doi.org/2327 [pii]

Abstract: Mycothiol is a low molecular weight thiol compound produced by a number of actinomycetes, and has been suggested to serve both anti-oxidative and detoxifying roles. To investigate the metabolism and the role of mycothiol in Streptomyces coelicolor, the biosynthetic genes (mshA, B, C, and D) were predicted based on sequence homology with the mycobacterial genes and confirmed experimentally. Disruption of the mshA, C, and D genes by PCR targeting mutagenesis resulted in no synthesis of mycothiol, whereas the mshB mutation reduced its level to about 10% of the wild type. The results indicate that the mshA, C, and D genes encode non-redundant biosynthetic enzymes, whereas the enzymatic activity of MshB (acetylase) is shared by at least one other gene product, most likely the mca gene product (amidase).

Molecular Cloning and Characterization of CMCase gene (celC) from Salmonella typhimurium UR: Ju-Soon Yoo , Youn-Ju Jung , Soo-Yeol Chung , Young-Choon Lee , Yong-Lark Choi; J. Microbiol. 2004;42(3):205-210.; DOI: https://doi.org/2088 [pii]

Abstract: The sequence coding for carboxymethylcellulase (CMCase, CelC) was isolated from the DNA of Salmonella typhimurium UR1. Comparison between the deduced amino acid sequence of CelC (368 amino acid residues, Molecular mass 41 kDa) and that of the previously published CMCase revealed that this enzyme belongs to the cellulase family 8 and D. The protein was overproduced in Escherichia coli using T7 expression system, and its activity was confirmed by CMC-SDS-PAGE. When the overexpressed CelC protein was tested on cellulose-type substrates, the recombinant protein is able to degrade cellulose-type substrates, such as CM-cellulose, xylan, avicel, lichenan, and laminarin. Optimal temperature and pH for enzyme activity were found to be 50^oC and pH 6.5, respectively.

Isolation and characterization of Bacillus sp. KD1014 producing carboxymethyl-cellulase: Lee, Kyung Dong , Kim, Jung Ho , Kim Hoon; J. Microbiol. 1996;34(4):305-310.

Abstract: A microorganism producing carboxymethyl-cellulase (CMCase) was isoalted from 300 soil and compost samples. The isolated was identified as Bacillus sp. by Biolog^TM test and fatty acid analysis, and named as Bacillus sp. KD1014. The isolate could degrade, in addition to CMC, various kinds of polysaccharides such as levan, xylan, starch, and filter paper but hardly degrade microcrystaline Avicel. The optimum growth and CMCase production of the isolate was observed between 16-and 25 hr-culture at 45℃ and pH 5.0. The maximum CMCase activity was observed at pH 4.5 and 60℃. The CMCase was found to bind to Avicel. The CMCase was internally cleaved as growth continued. When crude supernatant was used for activity staining, three major bands were detected on a native gel, however, only on major band was detected on a denaturating gel after removal of the detergent.

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