Title |
A comprehensive in silico analysis of sortase superfamily |
Author |
Adeel Malik and Seung Bum Kim* |
Address |
Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon 34134, Republic of Korea |
Bibliography |
Journal of Microbiology, 57(6),431–443, 2019,
|
DOI |
10.1007/s12275-019-8545-5
|
Key Words |
sortase, sequence similarity network, Actinobacteria,
Firmicutes, substrate recognition motif |
Abstract |
Sortases are cysteine transpeptidases that assemble surface
proteins and pili in their cell envelope. Encoded by all Grampositive
bacteria, few Gram-negative bacteria and archaea,
sortases are currently divided into six classes (A-F). Due to
the steep increase in bacterial genome data in recent years,
the number of sortase homologues have also escalated rapidly.
In this study, we used protein sequence similarity networks
to explore the taxonomic diversity of sortases and also to evaluate
the current classification of these enzymes. The resultant
data suggest that sortase classes A, B, and D predominate in
Firmicutes and classes E and F are enriched in Actinobacteria,
whereas class C is distributed in both Firmicutes and Actinobacteria
except Streptomyces family. Sortases were also observed
in various Gram-negatives and euryarchaeota, which
should be recognized as novel classes of sortases. Motif analysis
around the catalytic cysteine was also performed and
suggested that the residue at 2nd position from cysteine may
help distinguish various sortase classes. Moreover, the sequence
analysis indicated that the catalytic arginine is highly
conserved in almost all classes except sortase F in which arginine
is replaced by asparagine in Actinobacteria. Additionally,
class A sortases showed higher structural variation as compared
to other sortases, whereas inter-class comparisons suggested
structures of class C and D2 exhibited best similarities.
A better understanding of the residues highlighted in
this study should be helpful in elucidating their roles in substrate
binding and the sortase function, and successively could
help in the development of strong sortase inhibitors. |