Molecular and functional characterization of a c-type lysozyme from the Asian corn borer, Ostrinia furnacalis.
Some lepidopteran lysozymes have been reported to display activity against Gram-positive and Gram-negative bacteria, in contrast to most lysozymes that are active only against Gram-positive bacteria. OstrinLysC, a c-type lysozyme, was purified from the Asian corn borer, Ostrinia furnacalis Guenée (Lepidoptera: Pyralidae), and shows activity against Gram-positive and Gram-negative bacteria. The NH2-terminal amino acid sequence was determined by Edman degradation and used in a homology cloning strategy. The gene coding for OstrinLysC contains three exons and two introns. The expression profile of the OstrinlysC gene was examined by quantitative real-time PCR. Following injection of the larvae with bacteria, the OstrinlysC gene is strongly up-regulated in immune tissues. Transcripts were also detected in gut tissue. After feeding the larvae with bacteria, OstrinlysC transcripts increased in immune tissues. A very low level of transcript abundance was also detected in gut tissue. These results suggested that the OstrinlysC gene is involved in immune responses. The three dimensional structure of OstrinLysC was predicted. Based on comparison of the 3-D structure of OstrinLysC with that of silkworm lysozyme and chicken lysozyme, we hypothesize that the positive charge-rich surface and the short loop-2, which is close to the cluster of hydrophobic residues, may play important roles in the interaction with the outer membrane of Gram-negative bacterial cell walls.
Wang
Wen-Xian
WX
Department of Entomology, College of Natural Resource and Environment, South China Agricultural University, Guangzhou, 510642, PR China.
Wang
Yi-Peng
YP
Deng
Xiao-Juan
XJ
Dang
Xiang-Li
XL
Tian
Jin-Huan
JH
Yi
Hui-Yu
HY
Li
Yi-Feng
YF
He
Xiao-Fang
XF
Cao
Yang
Y
Xia
Qing-You
QY
Lai
Ren
R
Wen
Shuo-Yang
SY
Paskowitz
Susan
S
D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D005786:Gene Expression Regulation; D006458:Hemolymph / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009036:Moths / Q000201:enzymology* / Q000235:genetics*; D009113:Muramidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000494:pharmacology; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D013211:Staphylococcus aureus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D009113:Muramidase