Reconstitution of a minimal RNA degradosome demonstrates functional coordination between a 3' exonuclease and a DEAD-box RNA helicase.
The RNA degradosome is a multiprotein complex required for the degradation of highly structured RNAs. We have developed a method for reconstituting a minimal degradosome from purified proteins. Our results demonstrate that a degradosome-like complex containing RNase E, PNPase, and RhlB can form spontaneously in vitro in the absence of all other cellular components. Moreover, ATP-dependent degradation of the malEF REP RNA by the reconstituted, minimal degradosome is indistinguishable from that of degradosomes isolated from whole cells. The Rne protein serves as an essential scaffold in the reconstitution process; however, RNase E activity is not required. Rather, Rne coordinates the activation of RhlB dependent on a 3' single-stranded extension on RNA substrates. A model for degradosome-mediated degradation of structured RNA is presented with its implications for mRNA decay in Escherichia coli.
Coburn
G A
GA
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada.
Miao
X
X
Briant
D J
DJ
Mackie
G A
GA
D018528:ATP-Binding Cassette Transporters; D001483:Base Sequence; D002352:Carrier Proteins / Q000378:metabolism; D004722:Endoribonucleases / Q000378:metabolism* / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005092:Exonucleases / Q000378:metabolism / Q000502:physiology; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D009097:Multienzyme Complexes / Q000378:metabolism* / Q000502:physiology; D009690:Nucleic Acid Conformation; D011117:Polyribonucleotide Nucleotidyltransferase / Q000378:metabolism* / Q000502:physiology; D020365:RNA Helicases / Q000378:metabolism* / Q000502:physiology; D012329:RNA, Bacterial / Q000737:chemistry
D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D009097:Multienzyme Complexes; D012329:RNA, Bacterial; C111244:degradosome; C461599:maltose transport system, E coli; D011117:Polyribonucleotide Nucleotidyltransferase; D004722:Endoribonucleases; D005092:Exonucleases; C022650:spleen exonuclease; C022537:ribonuclease E; D020365:RNA Helicases