ATP-dependent degradation of SulA, a cell division inhibitor, by the HslVUprotease in Escherichia coli

HslVU is an ATP-dependent protease consisting of two multimeric components, the HslU ATPase and the HslV peptidase. To gain an insight into the role o f HslVU in regulation of cell division, the reconstituted enzyme was incuba ted with SulA, an inhibitor of cell division in Escherichia coli, or its fu sion protein with maltose binding protein (MBP), HslVU degraded both protei ns upon incubation with ATP but not with its nonhydrolyzable analog, ATP ga mma S, indicating that the degradation of SulA requires ATP hydrolysis, The pulse-chase experiment using an antibody raised against MBP-SulA revealed that the stability of SulA increased in hsl mutants and further increased i n lon/hsl double mutants, indicating that SulA is an in vivo substrate of H slVU as well as of protease La (Lon), These results suggest that HslVU in a ddition to Lon plays an important role in regulation of cell division throu gh degradation of SulA, (C) 1999 Federation of European Biochemical Societi es.