Cellular Oligomeric Assemblies: Structures by SSNMR and Integrated Methods

Bacterial division begins with the formation of a so-called “Z ring”, a tight bundle of many copies of a protein called FtsZ. The Z ring sits at the mid-cell and provides a “scaffold” on which bacteria assemble the factors needed for division. The Z ring also generates crucial forces to deform or pinch the membrane during division. Given its essential role in bacterial division, the Z ring has been identified as a prime target for antibiotic development. This project will determine the three-dimensional structure of the Z ring, in the various stages that appear through the cell division process and identify pockets on the Z ring that may be capable of binding compounds that inhibit division. The project will benefit society by recruiting and training talent for STEM; the PI’s lab has many accomplished female alums. The PI communicates these results through national graduate-level courses and workshops led or co-led by the PI, and local undergraduate and high school outreach programs. Since traditional structural biology methods are, for technical reasons, ill-suited to study the structure dynamics and drug binding of the Z ring, emerging nuclear magnetic resonance spectroscopy methods will be used to understand these key properties of the Z ring. While Cryo-EM images will be recorded and are expected to offer important insights, they typically have moderate or low resolution for E coli FtsZ. To complement these images, atomistic information will be obtained from solid state NMR. Room temperature solid state NMR data will be recorded, using latest generation sensitivity enhancement such as cryoprobe and proton detection. Low temperature NMR will also be recorded with sensitivity enhancement through dynamic nuclear polarization methods that appear to have advantages for detecting incisive long range interatomic distances. Selective detection of intermonomer interfaces will provide key information regarding quaternary contacts to define the oligomer structure. The structure in the presence of a potential antibiotic compound that arrests cell division, such as PC190723, in the presence of factors that assist in packing the oligomer, such as Zap A, and in the context of whole bacterial cells, will also be studied. This project is supported by the Molecular Biophysics Cluster of the Division of Molecular and Cellular Biosciences. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.