title: Evolution, homology conservation, and identification of unique sequence signatures in GH19 family chitinases.
abstract: The discovery of GH (Glycoside Hydrolase) 19 chitinases in Streptomyces sp. raises the possibility of the presence of these proteins in other bacterial species, since they were initially thought to be confined to higher plants. The present study mainly concentrates on the phylogenetic distribution and homology conservation in GH19 family chitinases. Extensive database searches are performed to identify the presence of GH19 family chitinases in the three major super kingdoms of life. Multiple sequence alignment of all the identified GH19 chitinase family members resulted in the identification of globally conserved residues. We further identified conserved sequence motifs across the major sub groups within the family. Estimation of evolutionary distance between the various bacterial and plant chitinases are carried out to better understand the pattern of evolution. Our study also supports the horizontal gene transfer theory, which states that GH19 chitinase genes are transferred from higher plants to bacteria. Further, the present study sheds light on the phylogenetic distribution and identifies unique sequence signatures that define GH19 chitinase family of proteins. The identified motifs could be used as markers to delineate uncharacterized GH19 family chitinases. The estimation of evolutionary distance between chitinase identified in plants and bacteria shows that the flowering plants are more related to chitinase in actinobacteria than that of identified in purple bacteria. We propose a model to elucidate the natural history of GH19 family chitinases.
authors.affiliation: Bioinformatics Centre (Centre of Excellence in Structural Biology and Bio-computing), Indian Institute of Science, Bangalore, India.
authors.forename: N A
authors.initials: NA
authors.lastname: Udaya Prakash
authors.forename: M
authors.initials: M
authors.lastname: Jayanthi
authors.forename: R
authors.initials: R
authors.lastname: Sabarinathan
authors.forename: P
authors.initials: P
authors.lastname: Kangueane
authors.forename: Lazar
authors.initials: L
authors.lastname: Mathew
authors.forename: K
authors.initials: K
authors.lastname: Sekar
mesh_terms: D039903:Actinobacteria / Q000235:genetics; D020816:Amino Acid Motifs; D001426:Bacterial Proteins / Q000235:genetics*; D002688:Chitinases / Q000235:genetics*; D030541:Databases, Genetic; D019143:Evolution, Molecular; D008958:Models, Molecular; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000235:genetics; D020560:Proteobacteria / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D010940:Plant Proteins; D002688:Chitinases