Studies on the bacteriophage MS2: VII. Structure determination of the longer polypurine sequences present in the pancreatic ribonuclease digest of the viral RNA

Abstract

The longest eight polypurine sequences present in bacteriophage MS2 RNA were isolated from a pancreatic ribonuclease digest by column chromatography, first at neutral and subsequently at acid pH. Each of them occurs only once in the viral RNA chain, as the molar yields approached unity for all eight oligonucleotides. The complete sequences were established by partial enzymic hydrolysis and separation of the products by paper ionophoretic methods. The structures were: GAAAGAGC ‡ ‡ In order to ensure clear and condensed representation of the polynucleotide sequences the one-letter symbols have been used for the 3′-nucleotides (cf. Brownlee, Sanger & Barrell, 1968). Thus A, C, G and U refer to adenosine 3′-phosphate, cytidine 3′-phosphate, guanosine 3′-phosphate and uridine 3′-phosphate, respectively. Unless specified otherwise, all oligonucleotides mentioned in this paper have a free 5′-terminal hydroxyl group and a 3′-terminal phosphate. , AAAGAAGU, GGAGAGAC, AGGGAGAAC, AGAGAAGGU, GGGAAAAGGU, AAAGAGAGGAC and GAGGAGAAAGC. There is no evidence of internal sequence homology in the RNA molecule. None of these polypurine sequences is part of the viral coat protein cistron.