The tail lysozyme complex of bacteriophage T4.
The tail baseplate of bacteriophage T4 contains a structurally essential, three-domain protein encoded by gene 5 in which the middle domain possesses lysozyme activity. The gene 5 product (gp5) undergoes post-translational cleavage, allowing the resultant N-terminal domain (gp5*) to assemble into the baseplate as a trimer. The lysozyme activity of the undissociated cleaved gp5 is inhibited until infection has been initiated, when the C-terminal portion of the molecule is detached and the rest of the molecule dissociates into monomers. The 3D structure of the undissociated cleaved gp5, complexed with gp27 (another component of the baseplate), shows that it is a cell-puncturing device that functions to penetrate the outer cell membrane and to locally dissolve the periplasmic cell wall.
Arisaka
Fumio
F
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, 226-8510, Yokohama, Japan. farisaka@bio.titech.ac.jp
Kanamaru
Shuji
S
Leiman
Petr
P
Rossmann
Michael G
MG
D017122:Bacteriophage T4 / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D046911:Macromolecular Substances; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D046911:Macromolecular Substances; D014764:Viral Proteins; C064431:gene 27 protein, Enterobacteria phage T4; C068293:gene 5 protein, Enterobacteria phage T4; D009113:Muramidase