Lysis protein T of bacteriophage T4.
Lysis protein T of phage T4 is required to allow the phage's lysozyme to reach the murein layer of the cell envelope and cause lysis. Using fusions of the cloned gene t with that of the Escherichia coli alkaline phosphatase or a fragment of the gene for the outer membrane protein OmpA, it was possible to identify T as an integral protein of the plasma membrane. The protein was present in the membrane as a homooligomer and was active at very low cellular concentrations. Expression of the cloned gene t was lethal without causing gross leakiness of the membrane. The functional equivalent of T in phage lambda is protein S. An amber mutant of gene S can be complemented by gene t, although neither protein R of lambda (the functional equivalent of T4 lysozyme) nor S possess any sequence similarity with their T4 counterparts. The murein-degrading enzymes (including that of phage P22) have in common a relatively small size (molecular masses of ca. 18,000) and a rather basic nature not exhibited by other E. coli cystosolic proteins. The results suggest that T acts as a pore that is specific for this type of enzyme.
Lu
M J
MJ
Max-Planck-Institut für Biologie, Tübingen, FRG.
Henning
U
U
D000469:Alkaline Phosphatase / Q000235:genetics; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D017122:Bacteriophage T4 / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics* / Q000502:physiology; D005798:Genes, Bacterial; D005814:Genes, Viral; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D010641:Phenotype; D010957:Plasmids; D015183:Restriction Mapping; D014764:Viral Proteins / Q000235:genetics*
D001425:Bacterial Outer Membrane Proteins; D014764:Viral Proteins; C078762:lysis protein T, bacteriophage T4; D000469:Alkaline Phosphatase