Factor that stimulates resuscitation of dormant cells. Has peptidoglycan (PG) hydrolytic activity. Active in the pM concentration range. Has little to no effect on actively-growing cells. PG fragments could either directly activate the resuscitation pathway of dormant bacteria or serve as a substrate for endogenous Rpf, resulting in low molecular weight products with resuscitation activity. Stimulates growth of stationary phase M.bovis (a slow-growing Mycobacterium), reduces the lag phase of diluted fast-growers M.smegmatis and Micrococcus luteus. Sequential gene disruption indicates RpfB and RpfE are higher than RpfD and RpfC in functional hierarchy. Expressed in actively growing cells, positively regulated by alternative sigma factor SigD, probably directly. Not essential, disruption of rpfC alone has no effect on growth or survival in liquid culture, nor in mouse infection models, although colony size is reduced. Alterations in gene expression are seen. All 5 genes in this family can be deleted without affecting growth in culture, however triple deletion mutants (rpfA-rpfC-rpfB or rpfA-rpfC-rpfD) are not able to resuscitate spontaneously in the presence or absence of O(2), and are attenuated in a mouse infection model. Belongs to the transglycosylase family. Rpf subfamily.