Natalia Mojica Cortés

• Kersten, Flore; Cortés, Natalia Mojica; Serrano, Albert; Heim, Joel Benjamin; Guyette, Jessica L. & Cezar, Henrique Musseli [Show all 11 contributors for this article] (2026). A Single Amino Acid in the A2 Linker of Cholera Toxin Affects the Efficiency of Toxin Disassembly and Resulting Toxicity. ACS Omega. 11(38), p. 57763–57780. doi: 10.1021/acsomega.6c07022. Full text in Research Archive Show summary

  Abstract Cholera toxin (CT) from Vibrio cholerae and heat-labile enterotoxin (LT) from enterotoxigenic Escherichia coli are highly related AB5-type protein toxins that contain a catalytic A1 subunit, an A2 linker, and a cell-binding homopentamer of B subunits. The two proteins bind the same GM1 receptor and have similar levels of enzymatic activity toward their shared Gsα target, yet CT is more potent than LT. This difference has been mapped to a sequence of 11 amino acids (residues 226–236) near the C-terminus of the A2 linker. We now identify a single amino acid, aspartic acid at position 229, as a key contributor to the function of CT: substituting it for glutamic acid 229 from LT reduced the toxicity of CT to the level of LT. Toxin disassembly by protein disulfide isomerase (PDI), which is an essential event in the intoxication process, was less efficient for CTD229E and LT than for wild-type CT. This was further confirmed by a CT variant, in which four residues were converted into the LT sequence (D229E, I230V, T232I, and H233Y). To test our previous hypothesis that the positioning of the A1 subunit over the B pentamer critically determines toxin disassembly and thus potency, we determined crystal structures of both toxin variants to 1.6 Å resolution and calculated the angle at which the A2 linker exits the pore. The conformations of the two toxin chimeras lie between CT and LT, with the A2 C-terminus of the CT quadruple variant adopting essentially the same fold as LT. The A subunits of the toxin variants as well as that of LT showed a higher conformational freedom than CT as determined by molecular dynamics simulations, suggesting that a more rigid positioning of the A subunit drives toxin disassembly and potency. Our collective data uncover the critical role of D229 in toxin folding and structural dynamics, which in turn impacts toxin potency through effects on the efficiency of PDI-driven toxin disassembly.

• Petersson, Marcus; Pettersen, Jens Sivkær; Henriksen, Helena Bay; Duzs, Ágnes; Fernández-Quintero, Monica L. & Burlet, Nick Jean [Show all 15 contributors for this article] (2025). Attenuating ETEC virulence using a heat-labile enterotoxin-blocking binding protein. Gut microbes. ISSN 1949-0976. 18(1). doi: 10.1080/19490976.2025.2597567. Full text in Research Archive Show summary

  Bacterial enteric pathogens are major contributors to the global burden of diarrheal diseases and the associated consequences for human health including malnutrition, growth stunting, morbidity, and mortality. While mortality from diarrhea has decreased, incidence remains high, and better interventions for preventing disease are needed. Single-domain antibodies (i.e., VHHs), functioning as target-binding proteins in the gastrointestinal tract, have been proposed as a potential approach to mitigate bacterial pathogenesis. Here, we describe a mitigation strategy where precision binding of a bivalent VHH to the receptor-binding B-pentamer of heat-labile enterotoxin aggregates the AB5 toxin and impairs enterotoxigenic Escherichia coli colonization in a flow chamber model simulating the human intestine. The VHH construct also binds to the structurally similar cholera toxin and effectively abrogates its intestinal cell cytotoxicity in vitro. Based on these results, we believe that targeting virulence could emerge as a new strategy for the management of bacterial enteric pathogens, supporting gut health in at-risk populations alongside vaccination campaigns or in populations without access to vaccines.

• Petersson, Marcus; Zingl, Franz G.; Rodriguez-Rodriguez, Everardo; Rendsvig, Jakob K. H.; Heinsøe, Heidi & Arendrup, Emma Wenzel [Show all 16 contributors for this article] (2025). Orally delivered toxin–binding protein protects against diarrhoea in a murine cholera model. Nature Communications. 16. doi: 10.1038/s41467-025-57945-w. Full text in Research Archive Show summary

  The ongoing seventh cholera pandemic, which began in 1961, poses an escalating threat to public health. There is a need for new cholera control measures, particularly ones that can be produced at low cost, for the one billion people living in cholera-endemic regions. Orally delivered VHHs, functioning as target-binding proteins, have been proposed as a potential approach to control gastrointestinal pathogens. Here, we describe the development of an orally deliverable bivalent VHH construct that binds to the B-pentamer of cholera toxin, showing that it inhibits toxin activity in a murine challenge model. Infant mice given the bivalent VHH prior to V. cholerae infection exhibit a significant reduction in cholera toxin–associated intestinal fluid secretion and diarrhoea. In addition, the bivalent VHH reduces V. cholerae colonization levels in the small intestine by a factor of 10. This cholera toxin–binding protein holds promise for protecting against severe diarrhoea associated with cholera.

• Cortés, Natalia Mojica; Kersten, Flore; Canals, Mateu Montserrat; III, G. Robb Huhn; Tislevoll, Abelone & Cordara, Gabriele [Show all 8 contributors for this article] (2023). Using Vibrio natriegens for High-Yield Production of Challenging Expression Targets and for Protein Perdeuteration. Biochemistry. ISSN 0006-2960. doi: 10.1021/acs.biochem.3c00612. Full text in Research Archive Show summary

  Production of soluble proteins is essential for structure/function studies; however, this usually requires milligram amounts of protein, which can be difficult to obtain with traditional expression systems. Recently, the Gram-negative bacterium Vibrio natriegens emerged as a novel and alternative host platform for production of proteins in high yields. Here, we used a commercial strain derived from V. natriegens (Vmax X2) to produce soluble bacterial and fungal proteins in milligram scale, which we struggled to achieve in Escherichia coli. These proteins include the cholera toxin (CT) and N-acetyl glucosamine-binding protein A (GbpA) from Vibrio cholerae, the heat-labile enterotoxin (LT) from E. coli and the fungal nematotoxin CCTX2 from Coprinopsis cinerea. CT, GbpA, and LT are secreted by the Type II secretion system in their natural hosts. When these three proteins were produced in Vmax, they were also secreted and could be recovered from the growth media. This simplified the downstream purification procedure and resulted in considerably higher protein yields compared to production in E. coli (6- to 26-fold increase). We also tested Vmax for protein perdeuteration using deuterated minimal media with deuterium oxide as solvent and achieved a 3-fold increase in yield compared to the equivalent protocol in E. coli. This is good news, since isotopic labeling is expensive and often ineffective but represents a necessary prerequisite for some structural biology techniques. Thus, Vmax represents a promising host for production of challenging expression targets and for protein perdeuteration in amounts suitable for structural biology studies.

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• Cortés, Natalia Mojica; Kersten, Flore; Serrano, Albert; Heim, Joel Benjamin; Cordara, Gabriele & Teter, Ken [Show all 8 contributors for this article] (2026). Why is cholera toxin more toxic than heat-labile enterotoxin? Insights from protein crystallography and MD simulations. Full text in Research Archive
• Cortés, Natalia Mojica; Kersten, Flore; Krengel, Ute; Teter, Ken; Cordara, Gabriele & Heim, Joel Benjamin [Show all 7 contributors for this article] (2024). Molecular insights into the differential toxicity of cholera toxin and heat-labile enterotoxin. Full text in Research Archive
• Cortés, Natalia Mojica; Kersten, Flore; Krengel, Ute; Cordara, Gabriele; Heim, Joel Benjamin & Teter, Ken [Show all 7 contributors for this article] (2024). Structural basis for the differential toxicity of cholera toxin and heat-labile enterotoxin. Full text in Research Archive
• Cortés, Natalia Mojica; Kersten, Flore; Krengel, Ute; Cordara, Gabriele; Serrano, Albert & Heim, Joel Benjamin [Show all 7 contributors for this article] (2024). Molecular insights into the differential toxicity of cholera toxin and heat-labile enterotoxin. Full text in Research Archive
• Crnic, Irene Fausk; Saragliadis, Athanasios; Cortés, Natalia Mojica; Kristiansen, Per Eugen & Krengel, Ute (2024). Molecular interactions between LPS and bacterial toxin. Full text in Research Archive

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