RNASE P RNA FROM PROCHLOROCOCCUS-MARINUS - CONTRIBUTION OF SUBSTRATE DOMAINS TO RECOGNITION BY A CYANOBACTERIAL RIBOZYME

The molecular organisation of the Prochlorococcus marinus rnpB gene an d the catalytic activity of the encoded RNA were characterised. Kineti c parameters for several pre-tRNA substrates were comparable to those from other eubacterial RNase P RNAs, although unusually high cation co ncentrations were required. The CCA-end of pre-tRNAs is essential for efficient turnover despite the lack of the canonical binding motif in P. marinus RNase P RNA. A trnR gene is located only 38 nt upstream the rnpB 5' end on the complementary strand. This arrangement resembles t hose in the plastids of Cyanophora and Porphyra but not in any other b acterium. (C) 1998 Federation of European Biochemical Societies.