SMolBNet 2.0: combining genetics and NMR to dissect fundamental protein-protein interactions for complex bacterial division

Abstract

Bacterial cell division is centrally dependent on FtsZ, a prokaryotic homolog of tubulin. FtsZ triggers division by assembling the "Z ring", a supramolecular structure made up of FtsZ polymers that surrounds the cell's periphery and functions as a scaffold for the bacterial division complex. Z ring formation is regulated by modulators, the generic name given to proteins that affect FtsZ polymerization either positively or negatively. Here, we propose a multidisciplinary approach as a way to unveil the molecular details of the interaction between FtsZ and three of its modulators: ZapA, MinC and MciZ. Genetic screens have identified FtsZ mutations that make the protein insensitive to the action of each of the three modulators. These mutations likely represent amino acid substitutions that affect FtsZ's binding site for these modiulators. In order to confirm and expand these findings, we propose the establishment of an NMR platform capable of measuring the interaction between FtsZ and its modulators, and of mapping, with atomic resolution, the contacts between these proteins. Establishing this platform will require initially the assignment of all FtsZ residues. Subsequently, this information will be used in 15N-HSQC chemical shift perturbation experiments with mixtures containing FtsZ and its modulators. A second goal of this project is solving the structure of MciZ, a 40 amino acid peptide with potent FtsZ inhibitory activity. In addition to the generation of novel information on a fundamental biological process, dissecting the structural and functional details of the interaction between FtsZ and inhibitors such as MciZ and MinC is bound to produce useful information for the rational design of bacterial cell division inhibitors. (AU)