Establishing Methods For Protein Purification And Activity Analysis For Pkn1 And Pkn5 From Chlamydia Trachomatis

Author

Spencer Hatfield, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2016

Degree Name

Master of Science

Department

Molecular Biology Microbiology and Biochemistry

First Advisor

Fisher, Derek

Abstract

Chlamydia are Gram negative, obligate intracellular bacterial pathogens responsible for diseases that affect both animals and humans. Only two vaccines have been developed for Chlamydia, targeting C. felis and C. abortus, and development of antibiotic resistance and/or persistent infection forms has been documented for multiple species. Consequently, identification of new therapeutic targets is critical for prevention and treatment of chlamydial infections. These bacterial pathogens have a unique biphasic developmental cycle beginning with the infectious and environmentally stable elementary body, which enters a host cell and envelopes itself in the host membrane forming an inclusion. While residing in the inclusion, the EB transitions into the metabolically active and replicative reticulate body. The RB divides by binary fission before converting back into the EB and exiting the host cell by inclusion extrusion or cell lysis. The signals that initiate morphogenesis and the mechanism(s) mediating the transition between EB and RB forms are poorly understood. Eukaryote-like serine/threonine kinases (Hank’s type kinases) have recently been described to play major roles in cellular development and pathogenicity in prokaryotes. Chlamydia encode three Hank’s type kinase; Pkn1, PknD, and Pkn5. We hypothesize that these kinases control bacterial differentiation and metabolism by regulating protein activity via phosphorylation, making them potential targets for anti-chlamydial therapeutics. To aid in future efforts to elucidate the roles of these Hank’s type kinases in the physiology of C. trachomatis, my thesis developed protocols for the affinity purification of recombinant Pkn1 and Pkn5 and assessed the efficacy of a high-throughput kinase assay for Pkn1.