title: Precursor nucleotides at the 5' end are not required for processing by RNase E at the 3' end of 5-S rRNA.
abstract: 7-S RNA, a single-site substrate for the processing enzyme RNase E of Escherichia coli, consists of p5 rRNA (the precursors of 5-S RNA) and the 3'-end region of the rRNA transcript which is mainly a termination stem and loop. The 7-S RNA studied here was derived mainly from the rRNA gene cluster rrnD, carried in a multicopy plasmid. It contains four different populations of molecules that differ from each other at their 5' ends only: the shortest species has the 5' end of the mature 5-S rRNA, while the others are one, two and three nucleotides longer. The four different 5'-end forms were separated in a long sequencing gel. Processing of these forms and unfractionated 7-S RNA by RNase E in vitro, showed that all forms, even the shortest one, can be processed to p5 rRNA. Since the extra nucleotides at the 5' end of the molecule could be base-paired with the region of 7-S RNA where RNase E cuts, it is concluded that this double-stranded structure is not required for the action of RNase E in separating the 3' end of p5 rRNA from the termination stem.
mesh_terms: D001482:Base Composition; D055598:Chemical Phenomena; D002621:Chemistry; D004722:Endoribonucleases; D004926:Escherichia coli / Q000378:metabolism; D009711:Nucleotides; D012329:RNA, Bacterial / Q000302:isolation & purification; D012335:RNA, Ribosomal; D013329:Structure-Activity Relationship; D014158:Transcription, Genetic
chemical_list: D009711:Nucleotides; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D004722:Endoribonucleases; C022537:ribonuclease E