Structural and functional characterization of a novel [alpha]/[beta] hydrolase from cariogenic pathogen Streptococcus mutans

• Published in: Proteins, structure, function, and bioinformatics Vol. 82; no. 4; pp. 695 - 700
• Main Authors: Wang, Zixi, Li, Lanfen, Su, Xiao-Dong
• Format: Journal Article
• Language: English
• Published: Hokoben Wiley Subscription Services, Inc 01.04.2014
• Subjects: Streptococcus mutans
• ISSN: 0887-3585; 1097-0134
• DOI: 10.1002/prot.24418

The protein Smu.1393c from Streptococcus mutans is annotated as a putative [alpha]/[beta] hydrolase, but it has low sequence identity to the structure-known [alpha]/[beta] hydrolases. Here we present the crystal structure of Smu.1393c at 2.0 Å resolution. Smu.1393c has a fully open alkaline substrate pocket, whose conformation is unique among other similar hydrolase structures. Three residues, Ser101, His251, and Glu125, were identified as the active center of Smu.1393c. By screening a series of artificial hydrolase substrates, we demonstrated Smu.1393c had low carboxylesterase activity towards short-chain carboxyl esters, which provided a clue for exploring the in vivo function of Smu.1393c. Proteins 2014; 82:695-700. © 2013 Wiley Periodicals, Inc. [PUBLICATION ABSTRACT]