RNase E enzymes from Rhodobacter capsulatus and Escherichia coli differ incontext- and sequence-dependent in vivo cleavage within the polycistronic puf mRNA

The 5' pufQ mRNA segment and the pufLMX mRNA segment of Rhodobacter capsula tus exhibit different stabilities. Degradation of both mRNA segments is ini tiated by RNase E-mediated endonucleolytic cleavage. While Rhodobacter RNas e E does not discriminate between the different sequences present around th e cleavage sites within pufQ and pufL, Escherichia coli RNase E shows prefe rence for the sequence harboring more A and U residues.