Structure and function of Enzymatic Membranes, Monica Olvera de la Cruz, Northwestern University, USA

Cells organize chemical reactions and functions in space by using organelles. Examples include mitochondria for energy production, or the nucleus for storing and passaging genetic information. Bacteria also contain diverse modes of subcellular organization, including protein bound organelles for compartmentalizing metabolic reactions, called bacterial microcompartments (MCPs). Bacterial MCPs are irregular polyhedral structures of about 140 nm in diameter on average. They are ubiquitous in enteric and other human pathogens, and help sequester toxic intermediates and prevent unwanted side reactions.  The specific type of bacterial microcompartment that I will be discussing is called the 1,2-propanediol utilization bacterial microcompartment, or the Pdu MCP, from Salmonella enterica serovar Typhimurium LT2. It has eight different proteins, PduA, PduJ, PduB and B prime, PduK, PduT, and PduU. In this talk, using molecular dynamics simulations and a continuum elastic model of multicomponent protein shells, I will show how to modify the structure and function of the microcompartments by deleting and mutating some of these proteins. Moreover, we show that these polyhedral MCPs present domains of segregated proteins on the shells that can be exploited to produce motion including chemotaxis and self diffusiophoresis.