A thermosensitive defect in the ATP binding pocket of FtsA can be suppressed by allosteric changes in the dimer interface

Summary In E scherichia coli , initial assembly of the Z ring for cell division requires FtsZ plus the essential Z ring‐associated proteins FtsA and ZipA . Thermosensitive mutations in ftsA , such as ftsA27 , map in or near its ATP binding pocket and result in cell division arrest at non‐permissive temperatures. We found that purified wild‐type FtsA bound and hydrolysed ATP , whereas FtsA27 was defective in both activities. FtsA27 was also less able to localize to the Z ring in vivo . To investigate the role of ATP transactions in FtsA function in vivo , we isolated intragenic suppressors of ftsA27 . Suppressor lesions in the ATP site restored the ability of FtsA27 to compete with ZipA at the Z ring, and enhanced ATP binding and hydrolysis in vitro . Notably, suppressors outside of the ATP binding site, including some mapping to the FtsA ‐ FtsA subunit interface, also enhanced ATP transactions and exhibited gain of function phenotypes in vivo . These results suggest that allosteric effects, including changes in oligomeric state, may influence the ability of FtsA to bind and/or hydrolyse ATP .