Cyanobacterial ribonucleic acid polymerases recognize lambda promoters.

We compared the initiation specificities in vitro of deoxyribonucleic acid-dependent ribonucleic acid polymerases purified from two cyanobacteria, Fremyella diplosiphon and Anacystis nidulans, and from Escherichia coli. A restriction fragment made from lambda deoxyribonucleic acid was used as a template. The cyanobacterial and E. coli ribonucleic acid polymerases recognized the same lambda promoters but exhibited different sensitivities to the inhibitor heparin, suggsesting differences in the structure of the initiation complexes.