Could be involved in the biosynthesis, transport or localization of poly-alpha-L-glutamine (PLG), a cell wall component. Contributes to stress tolerance and virulence. A member of the dormancy regulon. Induced in response to reduced oxygen tension (hypoxia), low levels of nitric oxide (NO), carbon monoxide (CO) and carbon dioxide (CO(2)). Expression peaks in the late log phase of growth. Disruption mutant shows reduced PLG content in the cell wall, increased sensitivity to chemical and mechanical agents, reduction of biofilm formation and attenuated virulence. Belongs to the CapA family.