Examining the promiscuous phosphatase activity of Pseudomonas aeruginosa arylsulfatase: A comparison to analogous phosphatases

Jinghui Luo, Bert van Loo, S. C.L. Kamerlin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Pseudomonas aeruginosa arylsulfatase (PAS) is a bacterial sulfatase capable of hydrolyzing a range of sulfate esters. Recently, it has been demonstrated to also show very high proficiency for phosphate ester hydrolysis. Such proficient catalytic promiscuity is significant, as promiscuity has been suggested to play an important role in enzyme evolution. Additionally, a comparative study of the hydrolyses of the p-nitrophenyl phosphate and sulfate monoesters in aqueous solution has demonstrated that despite superficial similarities, the two reactions proceed through markedly different transition states with very different solvation effects, indicating that the requirements for the efficient catalysis of the two reactions by an enzyme will also be very different (and yet they are both catalyzed by the same active site). This work explores the promiscuous phosphomonoesterase activity of PAS. Specifically, we have investigated the identity of the most likely base for the initial activation of the unusual formylglycine hydrate nucleophile (which is common to many sulfatases), and demonstrate that a concerted substrate-as-base mechanism is fully consistent with the experimentally observed data. This is very similar to other related systems, and suggests that, as far as the phosphomonoesterase activity of PAS is concerned, the sulfatase behaves like a "classical" phosphatase, despite the fact that such a mechanism is unlikely to be available to the native substrate (based on pK a considerations and studies of model systems). Understanding such catalytic versatility can be used to design novel artificial enzymes that are far more proficient than the current generation of designer enzymes.

Original languageEnglish
Pages (from-to)1211-1226
Number of pages16
JournalProteins: Structure, Function and Bioinformatics
Volume80
Issue number4
Early online date22 Dec 2011
DOIs
Publication statusPublished - 1 Apr 2012
Externally publishedYes

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