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- Title
Characterization of an extracellular protease and its cDNA from the nematode-trapping fungus Monacrosporium microscaphoides.
- Authors
Jinkui Yang; Ke-Qin Zhang; Miao Wang
- Abstract
To better exploit the biocontrol potential of nematophagous fungi, it is important to fully understand the molecular background of the infection process. In this paper, several nematode-trapping fungi were surveyed for nematocidal activity. From the culture filtrate of Monacrosporium microscaphoides, a neutral serine protease (designated Mlx) was purified by chromatography. This protease could immobilize the nematode Penagrellus redivivus in vitro and degrade its purified cuticle, suggesting that Mlx could serve as a virulence factor during infection. Characterization of the purified protease revealed a molecular mass of approximately 39 kDa, an isoelectric point of 6.8, and optimum activity at pH 9 at 65 °C. Mlx has broad substrate specificity, and it hydrolyzes protein substrates, including casein, skimmed milk, collagen, and bovine serum albumin. The gene encoding Mlx was also cloned and the nucleotide sequence was determined. The deduced amino acid sequence contained the conserved catalytic triad of aspartic acid – histidine – serine and showed high similarity with two cuticle-degrading proteases (PII and Aoz1), which were purified from the nematode-trapping fungus Arthrobotrys oligospora. Research on infection mechanisms of nematode-trapping fungi has thus far only focused on A. oligospora. However, little is known about other nematode-trapping fungi. Our report is among the first to describe the purification and cloning of an infectious protease from a different nematode-trapping fungus.
- Subjects
NEMATODE-destroying fungi; PREDACIOUS fungi; SERINE proteinases; PROTEINASES; CHROMATOGRAPHIC analysis; NUCLEOTIDE sequence
- Publication
Canadian Journal of Microbiology, 2006, Vol 52, Issue 2, p130
- ISSN
0008-4166
- Publication type
Article
- DOI
10.1139/W05-110