Date of Award
College of Arts & Sciences
Bachelor of Arts
The bacterial tubulin homologue FtsZ polymerizes in vitro in a GTP-dependent manner to form long, single stranded filaments. In cells, these filaments assemble at the nascent division site, interacting laterally to form the contractile Z ring. The Z ring serves as a scaffold for the rest of the division machinery and constricts at the leading edge of the invaginating septum during cytokinesis. The FtsZ polypeptide consists of three primary domains: the N-terminal globular core consisting of 315 residues that contains the GTP binding site, a variable and flexible C-terminal linker (CTL) consisting of 50 residues, and a conserved region at the C-terminus consisting of 17 residues required for interaction with modulatory proteins known as the grappling-hook peptide (GHP). Recently, the Levin lab has shown that the CTL behaves as a flexible intrinsically disordered peptide (IDP) and is required for FtsZ assembly in vitro and function in vivo. To gain insight into the role the CTL in FtsZ assembly, together with our collaborators Rohit Pappu and Anu Mittal, I am testing the structural parameters that define a functional CTL. Using computational predictions developed by the Pappu lab, we have generated six CTL variants in the context of native FtsZ: CTLV1-CTLV6. By changing the order and patterning of charged residues in the IDP sequence, these variants undertake conformations ranging from linear to globular or hairpin-like structures. To characterize the impact of these variants on FtsZ ring formation in vivo, I am assessing their impact on Z ring formation, growth and division in the model bacterium Bacillus subtilis. My preliminary data suggest a range of CTL conformations is tolerated. However, significantly more flexible or more rigid linkers can lead to instabiltity and aberrant FtsZ assembly in vivo. Experiments performed with synthetic CTL linkers yield results that support this conclusion.
Petra Anne Levin
Advisor/Committee Chair's Department
Department of Biology
Grigsby, Steven, "The C-terminal Linker of FtsZ Acts as an Intrinsically Disordered Peptide during Cell Division in Bacillus subtilis" (2015). Undergraduate Theses—Unrestricted. 31.