Domain organization and phylogenetic analysis of the chitinase-like family of proteins in three species of insects
- 作者：Qingsong Zhu ; Yasuyuki Arakane ; Debarshi Banerjee ; Richard W. Beeman ; Karl J. Kramer ; Subbaratnam Muthukrishnan
- 关键词：Chitinase ; Insect ; Phylogenetic analysis ; Chitin-binding domain ; Glycosylhydrolase ; Tribolium ; Anopheles ; Drosophila ; Chitin ; Cuticle ; Peritrophic membrane
- 刊名：Insect Biochemistry and Molecular Biology
- 出版年：2008
- 期刊代码：80_09651748
- 类别：bio
- 出版时间：April 2008
- 卷：38
- 期：4
- 页码：452-466
- 文件大小：501 K
摘要
A bioinformatics-based investigation of three insect species with completed genome sequences has revealed that insect chitinase-like proteins (glycosylhydrolase family 18) are encoded by a rather large and diverse group of genes. We identified 16, 16 and 13 putative chitinase-like genes in the genomic databases of the red flour beetle, Tribolium castaneum, the fruit fly, Drosophila melanogaster, and the malaria mosquito, Anopheles gambiae, respectively. Chitinase-like proteins encoded by this gene family were classified into five groups based on phylogenetic analyses. Group I chitinases are secreted proteins that are the most abundant such enzymes in molting fluid and/or integument, and represent the prototype enzyme of the family, with a single copy each of the catalytic domain and chitin-binding domain (ChBD) connected by an S/T-rich linker polypeptide. Group II chitinases are unusually larger-sized secreted proteins that contain multiple catalytic domains and ChBDs. Group III chitinases contain two catalytic domains and are predicted to be membrane-anchored proteins. Group IV chitinases are the most divergent. They usually lack a ChBD and/or an S/T-rich linker domain, and are known or predicted to be secreted proteins found in gut or fat body. Group V proteins include the putative chitinase-like imaginal disc growth factors (IDGFs). In each of the three insect genomes, multiple genes encode group IV and group V chitinase-like proteins. In contrast, groups I–III are each represented by only a singe gene in each species.