Journal of Microbiology

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

Screening, Purification, and Characterization of an Extracellular Prolyl Oligopeptidase from Coprinopsis clastophylla: Jen-Tao Chen , Mei-Li Chao , Chiou-Yen Wen , Wen-Shen Chu; J. Microbiol. 2012;50(4):652-659. Published online August 25, 2012; DOI: https://doi.org/10.1007/s12275-012-2099-0

Abstract: Culture filtrates of 22 mushrooms were screened for extracellular prolyl oligopeptidase activity. Four strains with relatively high enzyme activity were all from inky cap mushrooms. The production of Coprinopsis clastophylla prolyl oligopeptidase was associated with the growth of the fungus and the enzyme was not released by cell lysis. The enzyme was purified 285-fold to a specific activity of 52.05 U/mg. It was purified to a single band on a native polyacrylamide gel. However, the enzyme separated into three bands on a sodium dodecyl sulfate-polyacrylamide gel with mobility corresponding to molecular weights of approximately 84, 60, and 26 kDa. The results of tandem mass spectrometric analysis revealed that the 60 kDa protein was likely a degradation product of the 84 kDa protein. The isoelectric point of the purified enzyme was 5.2. The purified enzyme had an optimal pH and temperature of 8.0 and 37°C, respectively. Diisopropyl fluorophosphate (DFP), p-chloromercuribenzoaic acid (PCMB), Hg2+, and Cu2+ strongly inhibited C. clastophylla prolyl oligopeptidase. This enzyme is a serine peptidase and one or more cysteine residues of the enzyme are close to the active site.

Growth Inhibition of the Yeast Transformant by the Expression of a Chitinase from Coprinellus congregatus: Hyangsoon Lim , Hyoung T. Choi; J. Microbiol. 2010;48(5):706-708. Published online November 3, 2010; DOI: https://doi.org/10.1007/s12275-010-0272-x

Abstract: Coprinellus congregatus generates several chitinases during its entire life cycle: at the growing hyphal stage and at the mushroom autolysis stage. We have isolated a chitinase gene (chi1) from the mushroom tissue at the autolysing stage, and constructed a chitinase expression vector to get large amount of enzyme protein. Chitinase 1 (chi1) cDNA was heterologously expressed in Saccharomyces cerevisiae by gal1 promoter. The transformants showed no specific change in growth characteristics under normal growth conditions. However the expression of the gene by the gal1 promoter in the yeast transformants resulted in complete growth inhibition, while laccase expression by the gal1 promoter showed normal growth. The chitinase activities from the transformants were also more than 3 times higher than that of the recipient strain, and the chitinase expression by the real time-PCR also showed increased expression of the chi1 in the yeast transformant. Expression of a chitinase which was produced at the mushroom autolysing stage of C. congregatus resulted in yeast growth inhibition.

Note] Enhanced Expression of Chitinase during the Autolysis of Mushroom in Coprinellus congregatus: Hyangsoon Lim , Hyoung T. Choi; J. Microbiol. 2009;47(2):225-228. Published online May 2, 2009; DOI: https://doi.org/10.1007/s12275-008-0247-3

Abstract: Fungal cell walls consist of various glucans and chitin. An inky cap, Coprinellus congregatus, produced mushrooms at 25°C in a regime of 15 h light/9 h dark, and then the mushroom was autolyzed rapidly to generate black liquid droplets where no cell wall was detected by microscopy. A chitinase cDNA from the matured mushroom cells of C. congregatus that consisted of 1,541 nucleotides was successfully cloned using the rapid amplification of cDNA ends (RACE)-PCR technique. Its deduced 441 amino acid sequence had the conserved catalytic domain as in other fungal chitinase family 18. Chitinase activity was higher at the matured mushroom stage than primordial and young mushroom stage. When the expression of the cloned chitinase was examined by real-time PCR using the chitinase-specific primers, it was increased more than twice to 20 times during the autolytic process of mushroom than young mushroom or primordial stages, respectively.

Search