Edward Lopatto

Program: Plant and Microbial Biosciences

Current advisor: Scott J. Hultgren, PhD

Undergraduate university: Grinnell College, 2020

Enrollment year: 2020

Research summary
Conformational equilibrium of the Type 1 pilus adhesin FimH

Structurally, K. pneumoniae FimH is very similar to that of UPEC FimH, yet it demonstrates striking differences in function which suggests a shift in the conformational equilibrium. In UPEC FimH, there lacks a clear understanding of the molecular forces influencing conformation and deviations from the finely tuned equilibrium results in attenuation. In this project, I will test the hypothesis that K. pneumoniae FimH has a conformational equilibrium shifted towards the low-affinity tense state. I will identify FimH alleles that increase mannose binding in both bacterial and purified protein binding assays as an indicator of a conformational shift. I will then structurally characterize these alleles using X-ray crystallography. I will then test the relevance of the FimH conformational equilibrium in a murine acute UTI infection model. Previous UPEC FimH antibiotic sparing therapeutics, such as mannosides and a vaccine, have been very successful in treating both acute and chronic UPEC UTIs. I also hypothesize that monoclonal antibody (mAb) treatment options neutralizing K. pneumoniae and E. coli FimH will attenuate infection in a mouse model of UTI infection and that the sensitive conformational equilibrium can be a drug target of UPEC FimH. To test this, I will first structurally characterize monoclonal antibodies (mAbs) that inhibit K. pneumoniae and E. coli FimH binding in vitro and identify the effects on the conformational equilibrium.

Graduate publications
Lopatto EDB, Pinkner JS, Sanick DA, Potter RF, Liu LX, Bazán Villicaña J, Tamadonfar KO, Ye Y, Zimmerman MI, Gualberto NC, Dodson KW, Janetka JW, Hunstad DA, Hultgren SJ. 2024 Conformational ensembles in Klebsiella pneumoniae FimH impact uropathogenesis. Proc Natl Acad Sci USA, 121(39):e2409655121. PMCID: PMC11441496