GTP-bound E. coli FtsZ filaments are composed of Tense monomers: A DNP NMR study using interface detection.

FtsZ filaments are the major structural component of the bacterial Z-ring and are drivers of bacterial division. While crystal structures for FtsZ from some gram positive bacteria in the presence of GTP-analog like compounds suggest the possibility of a high energy "Tense" conformation, to date it remains an important question to elucidate whether this Tense form is the dominant form in filaments. Using dynamic nuclear polarization (DNP) solid-state NMR and differential isotopic labelling, we directly detect residues located at the inter-monomer interface of GTP-bound WT Escherichia coli FtsZ filaments. We combine chemical shift prediction, homology modelling, and heteronuclear dipolar recoupling techniques to characterize the E. coli FtsZ filament interface and demonstrate that the monomers in active filaments assume a Tense conformation.