- Mar 27, 2018
Date & Location: March 27, 2018, at 12p; Room 168 Plant Biology Building
Subject: Engineering modular protein membranes for electron transfer and enzyme scaffolding
Bacterial microcompartments (BMCs) are self-assembling intracellular organelles bounded by an entirely proteinaceous membrane. BMCs range in size from 40 to 600 nm in diameter and compartmentalize either anabolic (carboxysomes) or catabolic (metabolosomes) pathways. The protein membrane (or shell) is comprised predominantly of BMC-H and BMC-T proteins which form cyclic hexamers or trimers, respectively. Although homologs of these shell proteins are structurally similar, they can also be incredibly diverse; their sequences can be naturally permuted, they can incorporate inorganic cofactors, and they exhibit a variety of central pore sizes, shapes and charges that likely govern permeability of the shell.
Using tools developed in the Kerfeld lab for programming and controlling protein-protein interactions in vitro and in vivo, we will capitalize and expand on this native diversity of shell proteins by pursuing three parallel strategies for engineering new synthetic shells and scaffolds: i) permuting the primary structure of a BMC-H to enable encapsulation of translationally-fused cargo, ii) co-opting a proposed FeS cluster containing BMC-H protein to study electron transfer across the protein membrane, and iii) rationally designing amino acid mutations to alter the electrostatic properties of shell proteins for non-covalent scaffolding.
Our results highlight a remarkable flexibility in BMC shell assembly that enables the construction of a wide range of modular protein membranes for electron transfer and enzyme scaffolding.
Bryan is a postdoctoral associate in the lab of Cheryl Kerfeld.