Bacteroides are a major constituent of the gut microbiome of industrialized human populations. One of the most commonly detected species is Bacteroides ovatus. It has been linked to benefits like the suppression of intestinal inflammation but is also correlated with some autoimmune disorders. For example an overabundance of gut microbe Bacteroides ovatus has been observed in the autoimmune disorders systemic lupus erythematosus, Crohn’s disease, type I diabetes, irritable bowel disorder (IBD), and celiac disease.
Bacterial cell surface carbohydrates, like capsular polysaccharides (CPS), may play a role in modulating these varied host interactions. CPS form part of the outer capsule, protecting the expressing bacterium from environmental stressors such as antibiotics. Additionally, CPS are known to have an immunomodulatory effect on the host, which may explain their link to autoimmune diseases. Recent studies have begun to explore the diversity of CPS loci in Bacteroides; however, there is still much unknown.
Our research will provide further understanding of CPS in B. ovatus through characterization of proteins from biosynthetic loci, as they may be of interest for developing new therapies..
Project Milesones:
- June 2025: Collected several new BoPDA structures at ALS!
- May 2025: Thesis students Lydia Freedman ’25 and Salih Awouda ’25 present their research at the regional ACS meeting:
- December 2024: The paper about BoPDA was accepted to Biochemistry!! https://pubs.acs.org/doi/10.1021/acs.biochem.4c00519
- August 2024: We deposited four new structures of Bacteroides ovatus polysaccharide deacetylase (BoPDA) to the PDB!
- October 2021: Collected 1st high resolution crystallographic data set of BoPDA at ALS at Lawrence Berkeley National Lab!
Project Citations (* denotes Vassar College Undergraduate):
- Schwartz L.A.*, Norman J.O.*, Hasan S.*, Adamek O.E.*, Dzuong E.*, Lowenstein J.C.*, Yost O.G.*, Sankaran B., McLaughlin K.J. “Carbohydrate Deacetylase Unique to Gut Microbe Bacteroides Reveals Atypical Structure”. Biochemistry. 2025 Jan 7;64(1):180-191. (Epub 2024. Dec 11.) Pubmed PMID: 39663570.