An apaH mutation causes AppppA to accumulate and affects motility and catabolite repression in Escherichia coli.

Abstract
ApaH- mutants lack the hydrolase responsible for degradation of AppppN dinucleotides in Escherichia coli and show a .gtoreq.16-fold increase in appppA under nonstress conditions. These mutants lack detectable activity of .sigma.F, a factor required for transcription of motility and chemotaxis genes. Expression of the flbB/flaI operon, thought to encode .sigma.F, is decreased in apaH- mutants, and there appears to be a general decrease in expression of genes regulated by cAMP-binding protein and cAMP as well.