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A versatile nano display platform from bacterial spore coat proteins

Thursday, September 17, 2015 — Poster Session II

12:00 p.m. – 1:30 p.m.
FAES Terrace
NCI
MICROBIO-21

* FARE Award Winner

Authors

  • I Wu
  • KS Ramamurthi

Abstract

Bacterial spores are dormant cell types formed by some Gram-positive species in response to stressful conditions such as starvation. Spores protect the organism’s genetic material from environmental insults such as high heat, caustic chemicals, and radiation. Dormant bacterial spores are encased in a thick protein shell, the “coat”, which contains ~70 different proteins and is among the most durable static structures in biology. Coat morphogenesis initiates with the assembly of a basement layer, a platform on top of which the other coat proteins deposit. The structural component of the basement layer is composed of SpoIVA, an exceptional cytoskeletal protein that hydrolyzes ATP to drive its irreversible polymerization. SpoIVA is anchored to the surface of the forespore by SpoVM, a small amphipathic α-helical protein that localizes properly by sensing the positive membrane curvature of the forespore surface. Here, we reconstitute the basement layer of the coat atop spherical membranes supported by silica beads to create artificial spore-like particles. We report that these synthetic spore husk-encased lipid bilayers (SSHELs) assemble and polymerize into a static structure, mimicking in vivo basement layer assembly during sporulation in Bacillus subtilis. This system may provide a robust in vitro assay for studying spore morphogenesis that helps to reveal the mystery for spore coat assembly and interactions. Additionally, we demonstrate that SSHELs may be easily covalently modified with small molecules and proteins. We propose that SSHELs may be useful display platforms for drugs and vaccines in clinical settings, or for enzymes that neutralize pollutants for environmental remediation.

Category: Microbiology and Infectious Diseases