Structural and biochemical insights into the function and evolution of sulfoquinovosidases
Details
Publication Year 2018-09-26, Volume 4, Issue #9, Page 1266-1273
Journal Title
ACS Central Science
Publication Type
Journal Article
Abstract
An estimated 10 billion tonnes of sulfoquinovose (SQ) are produced and degraded each year. Prokaryotic sulfoglycolytic pathways catabolize sulfoquinovose (SQ) liberated from plant sulfolipid, or its delipidated form alpha-d-sulfoquinovosyl glycerol (SQGro), through the action of a sulfoquinovosidase (SQase), but little is known about the capacity of SQ glycosides to support growth. Structural studies of the first reported SQase (Escherichia coli YihQ) have identified three conserved residues that are essential for substrate recognition, but crossover mutations exploring active-site residues of predicted SQases from other organisms have yielded inactive mutants casting doubt on bioinformatic functional assignment. Here, we show that SQGro can support the growth of E. coli on par with d-glucose, and that the E. coli SQase prefers the naturally occurring diastereomer of SQGro. A predicted, but divergent, SQase from Agrobacterium tumefaciens proved to have highly specific activity toward SQ glycosides, and structural, mutagenic, and bioinformatic analyses revealed the molecular coevolution of catalytically important amino acid pairs directly involved in substrate recognition, as well as structurally important pairs distal to the active site. Understanding the defining features of SQases empowers bioinformatic approaches for mapping sulfur metabolism in diverse microbial communities and sheds light on this poorly understood arm of the biosulfur cycle.
Publisher
ACS
WEHI Research Division(s)
Chemical Biology
PubMed ID
30276262
Open Access at Publisher's Site
https://doi.org/10.1021/acscentsci.8b00453
Rights Notice
Refer to copyright notice on published article.


Creation Date: 2019-02-05 08:28:46
Last Modified: 2019-06-17 02:55:28
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