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High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
Joints formed by RecA protein from oligonucleotides and duplex DNA block initiation and elongation of transcription
E I Golub1, D C Ward, C M Radding
1Department of Genetics, Yale University School of Medicine, New Haven, CT 06510.
Abstract:
In the presence of the non-hydrolyzable analog of ATP, ATP gamma S, RecA protein can polymerize on an oligodeoxy-ribonucleotide to form a stable oligonucleoprotein filament that can find its homologous sequence in double-stranded DNA. The homologous joint formed by the oligonucleotide and duplex DNA is stable only if RecA protein is not removed. Such a nucleoprotein joint, covering a part or all of the promoter region of T3 or T7 phage RNA polymerase, blocked transcription directed by those polymerases. The same kind of joint, located downstream of the RNA polymerase promoter, also inhibited elongation of transcription and caused accumulation of truncated transcripts. These observations suggest that RecA protein can be used to shut off transcription from any promoter of known sequence.
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