Structure. 2017 Jan 3;25(1):79-93. doi: 10.1016/j.str.2016.11.008. Epub 2016 Dec 8.

Structural Basis for Regulation and Specificity of Fructooligosaccharide Import in Streptococcus pneumoniae.

Culurgioni S1, Harris G2, Singh AK3, King SJ4, Walsh MA5.

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Abstract

Streptococcus pneumoniae is dependent on carbohydrate uptake for colonization and pathogenesis, and dedicates over a third of its transport systems to their uptake. The ability of the pneumococcus to utilize fructooligosaccharides (FOSs) is attributed to the presence of one of two types of FOS ATP-binding cassette (ABC) transporters. Strains encoding SfuABC are only able to utilize short-chain FOSs, while strains encoding FusABC can utilize both short- and long-chain FOSs. The crystal structures of the substrate-binding protein FusA in its open and closed conformations bound to FOSs, and solution scattering data of SfuA, delineate the structural basis for import of short- and long-chain FOSs. The structure of FusA identifies an EF hand-like calcium-binding motif. This is shown to be essential for translocation of FOSs in FusABC and forms the basis for the definition of a new class of substrate-binding proteins that regulate substrate translocation by calcium.

Copyright © 2016 Diamond Light Source Ltd. Published by Elsevier Ltd.. All rights reserved.

KEYWORDS:

Streptococcus pneumoniae; calcium signaling; carbohydrate ABC transporters; substrate translocation regulation; substrate-binding proteins

PMID: 27939783 DOI: 10.1016/j.str.2016.11.008

[PubMed - in process]