Download MendeleyStructural and Functional Characterization of Stx2k, a New Subtype of Shiga Toxin 2.
Hughes, A.C., Zhang, Y., Bai, X., Xiong, Y., Wang, Y., Yang, X., Xu, Q., He, X.(2019) Microorganisms 8
- PubMed: 31861375
- DOI: https://doi.org/10.3390/microorganisms8010004
- Primary Citation of Related Structures:
6U3U - PubMed Abstract:
Shiga toxin (Stx) is the major virulence factor of Shiga toxin-producing Escherichia coli (STEC). Stx evolves rapidly and, as such, new subtypes continue to emerge that challenge the efficacy of existing disease management and surveillance strategies. A new subtype, Stx2k, was recently identified in E. coli isolated from a wide range of sources including diarrheal patients, animals, and raw meats, and was poorly detected by existing immunoassays. In this study, the structure of Stx2kE167Q was determined at 2.29 Å resolution and the conservation of structure with Stx2a was revealed. A novel polyclonal antibody capable of neutralizing Stx2k and an immunoassay, with a 10-fold increase in sensitivity compared to assays using extant antibodies, were developed. Stx2k is less toxic than Stx2a in Vero cell assays but is similar to Stx2a in receptor-binding preference, thermostability, and acid tolerance. Although Stx2k does not appear to be as potent as Stx2a to Vero cells, the wide distribution and blended virulence profiles of the Stx2k-producing strains suggest that horizontal gene transfer through Stx2k-converting phages could result in the emergence of new and highly virulent pathogens. This study provides useful information and tools for early detection and control of Stx2k-producing E. coli , which could reduce public risk of infection by less-known STECs.
Organizational Affiliation:
Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, 800 Buchanan St., Albany, CA 94710, USA.
