Cloning and characterization of an extracellular serine protease from the nematode-trapping fungus Arthrobotrys conoides.
An extracellular serine protease (Ac1) with a molecular mass of 35 kDa was purified from the nematode-trapping fungus Arthrobotrys conoides. The optimum activity of Ac1 is at pH 7.0 and 53.2 degrees C (over 20 min). Ac1 can degrade a broad range of substrates including casein, gelatin, bovine serum albumin, collagen, and nematode cuticles. Moreover, the enzyme can immobilize the free-living nematode Panagrellus redivivus and the pine wood nematode Bursaphelenchus xylophilus, indicating Ac1 may be involved in infection against nematodes. The encoding gene of Ac1 contains one intron of 60-bp and two exons encoding a polypeptide of 411 amino acid residues. The deduced polypeptide sequence of Ac1 showed a high degree of similarity to two previously reported serine proteases PII and Mlx from other nematode-trapping fungi (81% aa sequence identity). However, three proteases Ac1, Aoz1 and Mlx showed optimum temperatures at 53.2, 45 and 65 degrees C, respectively. Compared to PII, Ac1 appears to have a significantly higher activity against gelatin, bovine serum albumin, and non-denatured collagen. Moreover, our bioassay experiments showed that Ac1 is more effective at immobilizing P. redivivus than B. xylophilus.
Yang
Jinkui
J
Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming, 650091, People's Republic of China.
Li
Juan
J
Liang
Lianming
L
Tian
Baoyu
B
Zhang
Ying
Y
Cheng
Chunmei
C
Zhang
Ke-Qin
KQ
D000595:Amino Acid Sequence; D000818:Animals; D001203:Ascomycota / Q000201:enzymology* / Q000472:pathogenicity; D003001:Cloning, Molecular; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009348:Nematoda / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology*; D010802:Phylogeny; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature
D012697:Serine Endopeptidases