Protein-RNA interactions in the active center of transcription elongation complex.
By using a crosslinkable probe incorporated into the 3' terminus of nascent transcript, three sites were mapped in Escherichia coli RNA polymerase that are contacted by the RNA in the productive elongation complex. Two of these sites are in the beta subunit and one is in the beta' subunit. During elongation, the transcription complex occasionally undergoes an arrest whereby it can neither extend nor release the RNA transcript. It is demonstrated that in an arrested complex, the three contacts of RNA 3' terminus are lost, while a new beta' subunit contact becomes prominent. Thus, elongation arrest appears to involve the disengagement of the bulk of the active center from the 3' terminus of RNA and the transfer of the terminus into a new protein environment.
Markovtsov
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V
The Public Health Research Institute, New York, NY 10016, USA.
Mustaev
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Goldfarb
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D000345:Affinity Labels; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001665:Binding Sites; D002874:Chromosome Mapping; D003432:Cross-Linking Reagents; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015335:Molecular Probes; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012329:RNA, Bacterial / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D000345:Affinity Labels; D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D015335:Molecular Probes; D012329:RNA, Bacterial; D012321:DNA-Directed RNA Polymerases