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. 1973 Jan;11(1):116–128. doi: 10.1128/jvi.11.1.116-128.1973

Electrophoretic and Other Properties of Bacteriophage Qβ: the Effect of a Variable Number of Read-Through Proteins

Roger J Radloff a,1, Paul Kaesberg a
PMCID: PMC355067  PMID: 4567683

Abstract

When subjected to electrophoresis in polyacrylamide gels, the virions of wild-type Qβ bacteriophage are found in a single, major, anomalously wide band. With Qβ mutant 27-2, this wide band is replaced by a set of narrow, well-defined bands. The most rapidly migrating band of the mutant, comprising less than 10% of the total, contains defective virions. These virions have sedimentation coefficients ranging from 70 to 100% of the bulk of the unfractionated mutant, they contain no read-through protein (protein IIb), and they are deficient in maturation protein and contain fragmented RNA. The second band, comprising less than 3% of the total virus, has not been well characterized. The virions in the remaining electrophoretic bands are infective. Their distribution into bands is believed due to differences in their effective volume resulting from differences in their content of protein IIb. The most rapidly migrating band of this series contains virions with a few molecules of IIb protein, whereas the more slowly migrating bands contain virions with a larger number of IIb molecules. The adjacent bands in the series contain virions which differ by approximately three IIb molecules. Wild-type Qβ virus is similar to the mutant in that the more slowly migrating virions contain more protein IIb than the more rapidly migrating virions. Their failure to resolve into distinct bands upon electrophoresis is believed due to a less restricted packing of protein IIb into their virions. Both wild-type Qβ and mutant 27-2 also have 1 to 5% of the virions in the form of dimers which migrate with approximately one-half the mobility of the respective monomer forms. When the average amount of IIb per virion is increased by growth of the virus in a UGA suppressor strain, the electrophoretic pattern is altered. In the case of wild-type Qβ, the single band is wider, whereas with Qβ mutant 27-2 there occurs an increased number of partially resolved narrow bands. We suggest that the structural feature responsible for the difference in electrophoretic pattern between mutant 27-2 and wild-type Qβ is the mode of IIb packing in the virions. In the mutant, the IIb proteins are found in the virions only in multiples of three, whereas wild-type virions may differ by only a single IIb protein.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Craven G. R., Voynow P., Hardy S. J., Kurland C. G. The ribosomal proteins of Escherichia coli. II. Chemical and physical characterization of the 30S ribosomal proteins. Biochemistry. 1969 Jul;8(7):2906–2915. doi: 10.1021/bi00835a032. [DOI] [PubMed] [Google Scholar]
  2. Garwes D., Sillero A., Ochoa S. Virus-specific proteins in Escherichia coli infected with phage Qb. Biochim Biophys Acta. 1969 Jul 22;186(1):166–172. doi: 10.1016/0005-2787(69)90499-7. [DOI] [PubMed] [Google Scholar]
  3. Horiuchi K., Webster R. E., Matsuhashi S. Gene products of bacteriophage Q beta. Virology. 1971 Aug;45(2):429–439. doi: 10.1016/0042-6822(71)90343-6. [DOI] [PubMed] [Google Scholar]
  4. Jockusch H., Ball L. A., Kaesberg P. Synthesis of polypeptides directed by the RNA of phage Q beta. Virology. 1970 Oct;42(2):401–414. doi: 10.1016/0042-6822(70)90283-7. [DOI] [PubMed] [Google Scholar]
  5. Lane L. C., Kaesberg P. Multiple genetic components in bromegrass mosaic virus. Nat New Biol. 1971 Jul 14;232(28):40–43. doi: 10.1038/newbio232040a0. [DOI] [PubMed] [Google Scholar]
  6. Moore C. H., Farron F., Bohnert D., Weissmann C. Possible origin of a minor virus specific protein (A1) in Q-beta particles. Nat New Biol. 1971 Sep 15;234(50):204–206. doi: 10.1038/newbio234204a0. [DOI] [PubMed] [Google Scholar]
  7. Overby L. R., Barlow G. H., Doi R. H., Jacob M., Spiegelman S. Comparison of two serologically distinct ribonucleic acid bacteriophages. I. Properties of the viral particles. J Bacteriol. 1966 Jan;91(1):442–448. doi: 10.1128/jb.91.1.442-448.1966. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. STRAUSS J. H., Jr, SINSHEIMER R. L. Purification and properties of bacteriophage MS2 and of its ribonucleic acid. J Mol Biol. 1963 Jul;7:43–54. doi: 10.1016/s0022-2836(63)80017-0. [DOI] [PubMed] [Google Scholar]
  9. Silverman P. M., Mobach H. W., Valentine R. C. Sex hair (F-pili) mutants of E. coli. Biochem Biophys Res Commun. 1967 May 5;27(3):412–416. doi: 10.1016/s0006-291x(67)80115-3. [DOI] [PubMed] [Google Scholar]
  10. Staples D. H., Hindley J. Ribosome binding site of Q-beta RNA polymerase cistron. Nat New Biol. 1971 Sep 15;234(50):211–212. doi: 10.1038/newbio234211a0. [DOI] [PubMed] [Google Scholar]
  11. Steitz J. A. Oligonucleotide sequence of replicase initiation site in Q RNA. Nat New Biol. 1972 Mar 22;236(64):71–75. doi: 10.1038/newbio236071a0. [DOI] [PubMed] [Google Scholar]
  12. Strauss E. G., Kaesberg P. Acrylamide gel electrophoresis of bacteriophage Q beta: electrophoresis of the intact virions and of the viral proteins. Virology. 1970 Oct;42(2):437–452. doi: 10.1016/0042-6822(70)90287-4. [DOI] [PubMed] [Google Scholar]
  13. Sugiyama T., Hebert R. R., Hartman K. A. Ribonucleoprotein complexes formed between bacteriophage MS2 RNA and MS2 protein in vitro. J Mol Biol. 1967 May 14;25(3):455–463. doi: 10.1016/0022-2836(67)90198-2. [DOI] [PubMed] [Google Scholar]
  14. Swank R. T., Munkres K. D. Molecular weight analysis of oligopeptides by electrophoresis in polyacrylamide gel with sodium dodecyl sulfate. Anal Biochem. 1971 Feb;39(2):462–477. doi: 10.1016/0003-2697(71)90436-2. [DOI] [PubMed] [Google Scholar]
  15. Weber K., Osborn M. The reliability of molecular weight determinations by dodecyl sulfate-polyacrylamide gel electrophoresis. J Biol Chem. 1969 Aug 25;244(16):4406–4412. [PubMed] [Google Scholar]
  16. Weiner A. M., Weber K. Natural read-through at the UGA termination signal of Q-beta coat protein cistron. Nat New Biol. 1971 Sep 15;234(50):206–209. doi: 10.1038/newbio234206a0. [DOI] [PubMed] [Google Scholar]
  17. Yamamoto K. R., Alberts B. M., Benzinger R., Lawhorne L., Treiber G. Rapid bacteriophage sedimentation in the presence of polyethylene glycol and its application to large-scale virus purification. Virology. 1970 Mar;40(3):734–744. doi: 10.1016/0042-6822(70)90218-7. [DOI] [PubMed] [Google Scholar]

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