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Calcium-Mediated Protein Folding and Stabilisation of Salmonella Biofilm-Associated Protein a

Guttula, D., Yao, Mingxi, Baker, Karen, Liang, Y., Goult, Benjamin T, Doyle, P.S., Yan, Jie (2019) Calcium-Mediated Protein Folding and Stabilisation of Salmonella Biofilm-Associated Protein a. Journal of Molecular Biology, 431 (2). pp. 433-443. ISSN 0022-2836. E-ISSN 1089-8638. (doi:10.1016/j.jmb.2018.11.014)

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https://doi.org/10.1016/j.jmb.2018.11.014

Abstract

Biofilm-associated proteins (BAPs) are important for early biofilm formation (adhesion) by bacteria and are also found in mature biofilms. BapA from Salmonella is a ~386 kDa surface protein, comprised of 27 tandem repeats predicted to be bacterial Ig-like (BIg) domains. Such tandem repeats are conserved for BAPs across different bacterial species, but the function of these domains is not completely understood. In this work, we report the first study of the mechanical stability of the BapA protein. Using magnetic tweezers, we show that the folding of BapA BIg domains requires calcium- binding and the folded domains have differential mechanical stabilities. Importantly, we identify that >100 nM concentration of calcium is needed for folding of the BIg domains, and the stability of the folded BIg domains is regulated by calcium over a wide concentration range from sub-micromolar (?M) to millimolar (mM). Only at mM calcium concentrations, as found in the extracellular environment, do the BIg domains have the saturated mechanical stability. BapA has been suggested to be involved in Salmonella invasion, and it is likely a crucial mechanical component of biofilms. Therefore, our results provide new insights into the potential roles of BapA as a structural maintenance component of Salmonella biofilm and also Salmonella invasion.

Item Type: Article
DOI/Identification number: 10.1016/j.jmb.2018.11.014
Uncontrolled keywords: Magnetic tweezers; Calcium-binding protein; Mechanical stability of proteins; Biofilm-associated protein, Salmonella
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Ben Goult
Date Deposited: 22 Nov 2018 11:54 UTC
Last Modified: 16 Nov 2019 00:00 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/70226 (The current URI for this page, for reference purposes)
Goult, Benjamin T: https://orcid.org/0000-0002-3438-2807
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