Outer-membrane proteins induced by T4 bacteriophage

Many T4-induced proteins were found associated with the Escherichia coli membrane during infection. Some of these were apparently sonically bound, but many could be identified as integral parts of the inner and outer bacterial membranes by their selective solubilities in guanidine or Sarkosyl. The synthesis and insertion of these proteins into the bacterial membrane were temporally controlled and, once in the membrane, these proteins were stably integrated. Host membrane protein synthesis continued after infection of non-UV-irradiated cells, but was not present if the cells were irradiated. There was no major redistribution or loss of bacterial proteins from E. coli membranes as a consequence of T4 infection.

Section: Am__~~~a Lsupporting

confidence: 91%

mentioning

confidence: 99%

Alteration of the Escherichia coli membrane by addition of bacteriophage T4 protein synthesized after infection

Ennis¹,

Kievitt²

1977

“…The supernatant containing T4D was returned to 37°C, and 40 Ml of a saturated MgSO4 solution, 40 Mg of bovine pancreatic DNase I (Sigma Chemical Co.), and 40 Mg of RNase A (bovine pancreas; Sigma type II-A) were added. After 30 min, the phage were pelleted by centrifugation in a Beckman type 35 rotor at 35,000 rpm for 45 min at 5°C. The pellet was suspended gently in 0.4 ml of M9 salts, and the large pieces of insoluble debris were removed manually by holding the centrifuge tube horizontally and rotating it.…”

Section: Methodsmentioning

confidence: 99%

Bacteriophage T4 Virion Dihydrofolate Reductase: Approaches to Quantitation and Assessment of Function

Mosher

DiRenzo

Mathews

1977

This paper is concerned with the physiological role(s) of T4 phage-coded dihydrofolate reductase, which functions both in DNA precursor metabolism and as a virion protein. (i) We have detected enzyme activity in noninfectious particles produced under restrictive conditions by gene 11 mutants. This supports the conclusion of Kozloff et al. (J. Virol. 16:1401-1408, 1975) that the protein lies in the baseplate, covered by the gene 11 protein. (ii) We have obtained further evidence for virion dihydrofolate reductase as the target for neutralizing activity of T4 dihydrofolate reductase antiserum and as a determinant ofthe heat lability of the virion. This derives from our observation that the reductases specified by T4B and T4D differ in several properties. (iii) We have investigated several anomalous properties of T4 mutants bearing deletions that reportedly extend into or through the frd gene, which codes for dihydrofolate reductase. Evidence is presented that the deletions in fact do not extend through frd. These strains direct the synthesis of material that cross-reacts with antiserum to homogeneous dihydrofolate reductase. Moreover, they are all quite sensitive to the phage-neutralizing effects of this antiserum. In addition, they are restricted by several of the hospital strains, wild-type strains ofEscherichia coli supplied by the California Institute of Technology group. (iv) We have attempted to detect dihydrofolate reductase among early-synthesized proteins present in T4 tails. Two such proteins are seen, one of which is evidently the gene 25 product and one that is a bacterial protein. Quantitation of our electrophoretic technique has allowed determination of the number of molecules of some T4 tail components present per virion. (v) Finally, we have compared the T4 dihydrofolate reductase with the corresponding enzyme specified by two plasmids conferring resistance to trimethoprim (Skold and Widh, J. Biol. Chem. 249:4324-4325, 1974). Although the enzymes are similar in some properties, they differ in several important respects, including immunological activity.

“…The samples for these gels were protein fractions from urea-acetic acid gels. They were obtained from small areas (about 3 by 25 mm) cut from the dried gels, suspended in 0.7 ml of sodium dodecyl sulfate gel sample buffer plus 35 ,l of Tris, and eluted at 5°C for 7 days. Samples of the eluates were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis.…”

Section: Sodium Dodecyl Sulfate Gel Electrophoresismentioning

confidence: 99%

Protein induced by bacteriophage T4 which is absent in Escherichia coli infected with nuclear disruption-deficient phage mutants

Koerner¹,

Thies²,

Snustad³

1979

A protein induced by wild-type T4 phage which is absent in Escherichia coli infected with nuclear disruption-deficient phage (with mutations in gene ndd) was identified by polyacrylamide gel electrophoresis. This protein was synthesized at maximum rate at 3 to 6 min after infection. It had a molecular weight of 15,000 determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was associated with sedimentable fractions of the cell from which it can be dissociated