Structural analysis of OmpR a transcription regulator in the mutualistic bacterium, Xenorhabdus nematophila

Abstract

A partnership between Marquette University High School students participating in the MSOE SMART Team (Students Modeling A Research Topic) program and a researcher enabled the team to explore structure and function, and to build a physical model using 3D printing technology, of OmpR. OmpR is a transcription factor necessary for the nutrition gathering strategy of the bacterium Xenorhabdus nematophila. Bacteria absorb food through membrane pores, which change in size to optimize food intake and to protect themselves from toxins.X. nematophila has sensor proteins in the outer membrane. When food touches an outer membrane receptor (EnvZ), the receptor transfers phosphate to OmpR forming OmpR‐P, which can bind to DNA. When nutrients are abundant, OmpR‐P binds to OmpC, a gene promoting formation of a small pore, allowing food yet limiting influx of toxins. When food is scarce, OmpR‐P binds OmpF, a gene promoting formation of a large pore, allowing more food intake and growth of a flagellum enabling movement to a nutrient rich location.The OmpR gene is also responsible for production of antibiotic compounds that combat a broad range of microorganisms. X. nematophila often forms a mutualistic relationship with nematodes. The bacterium‐nematode pair seek to inhabit and eventually kill certain insects, benefiting from the nutrients provided by the insect's corpse.Supported by a grant from NIH‐NCRR‐SEPA