Purification of the Messenger RNA Cap-Binding Protein Using a New Affinity Medium

Nancy R. Webb, Robert E. Rhoads, Ravi V.J. Chari, Gia DePillis, John W. Kozarich

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


The p-aminophenyl γ-ester of γ-methylguanosine 5′-triphosphate (m7 GTP) was synthesized and coupled to Sepharose 4B. A 0.5 M salt extract of rabbit reticulocyte ribosomes was passed over a column containing the affinity medium. After extensive washing, a solution of m7GTP was passed through the column, and a single polypeptide species of 24 kilodaltons (kDa) was eluted. This had an electrophoretic mobility identical with that of the mRNA cap-bindingprotein. This assignment was confirmed by the fact that the eluted material was enriched nearly 200-fold in the ability to specifically bind 32P-labeled capped oligonucleotides. A control affinity medium consisting of GTP similarly coupled to Sepharose failed to retain the 24-kDa species. The postribosomal supernatant fraction yielded slightly more of the 24-kDa species than the ribosomal wash fraction when passed over this affinity medium.

Original languageEnglish
Pages (from-to)177-181
Number of pages5
Issue number2
StatePublished - Jan 1984

ASJC Scopus subject areas

  • Biochemistry


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