Structural basis for the role of serine-rich repeat proteins from Lactobacillus reuteri in gut microbe-host interactions

Sequeira, Saannya, Kavanaugh, Devon, Mackenzie, Donald, Suligoj, Tanja, Walpole, Samuel, Leclaire, Charlotte, Gunning, A. P., Latousakis, Dimitrios, Willats, William, Angulo, Jesus ORCID:, Dong, Changjiang and Juge, Nathalie (2018) Structural basis for the role of serine-rich repeat proteins from Lactobacillus reuteri in gut microbe-host interactions. Proceedings of the National Academy of Sciences of the United States of America (PNAS), 115 (12). E2706-E2715. ISSN 1091-6490

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Lactobacillus reuteri, a Gram-positive bacterial species inhabiting the gastrointestinal tract of vertebrates displays remarkable host adaptation. Previous mutational analyses of rodent strain L. reuteri 100-23C identified a gene encoding a predicted surface-exposed serine-rich repeat protein (SRRP100-23) that was vital for L. reuteri biofilm formation in mice. SRRPs have emerged as an important group of surface proteins on many pathogens but no structural information is available in commensal bacteria. Here we report the 2.00 Å and 1.92 Å crystal structures of the binding regions (BRs) of SRRP100-23 and SRRP53608 from L. reuteri ATCC 53608, revealing a unique “β-solenoid” fold in this important adhesin family. BRSRRP53608 boundto host epithelial cells and DNA at neutral pH and recognised polygalacturonic acid (PGA), rhamnogalacturonan I or chondroitin sulfate A at acidic pH. Mutagenesis confirmed the role of the BR putative binding site in the interaction of BRSRRP53608 with PGA. Long molecular dynamics simulations showed that SRRP53608 undergoes a pH-dependent conformational change. Together, these findings shed new mechanistic insights into the role of SRRPs in host-microbe interactions and open new avenues of research into the use of biofilm-forming probiotics against clinically important pathogens.

Item Type: Article
Additional Information: Data deposition: The structure factors and coordinates reported in this work have been deposited in the Protein Data Bank (PBD), [accession ID codes 5NXK (SRRP53608-BR) and 5NY0 (SRRP100-23-BR)]. This article contains supporting information online at
Faculty \ School: Faculty of Science > School of Pharmacy
Faculty of Medicine and Health Sciences > Norwich Medical School
Faculty of Science > School of Biological Sciences
UEA Research Groups: Faculty of Science > Research Groups > Pharmaceutical Materials and Soft Matter
Faculty of Medicine and Health Sciences > Research Groups > Gastroenterology and Gut Biology
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Depositing User: Pure Connector
Date Deposited: 02 Feb 2018 16:30
Last Modified: 24 Aug 2023 02:30
DOI: 10.1073/pnas.1715016115

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