Jonathan King (1970) FEBS Symposium, 21, 171-190

Steps in T4 tail core assembly


The functions of 21 phage genes are required for the fromation of the T4 tail. Thre of these genes, 19, 48 and 54, are necessary for the assembly of the tail core on the baseplate. Cells infected under restricive conditions with mutants in these genes accumulate free baseplates. These have been characterized by electron microscopy, centrifugation and serology. Th three classes are morphologically indistinguishable; however, baseplates from 48- mutants form dimers between their inner faces. After isolation by sedimentatin the 3 classes of baseplates have been characterized and differentiated by the in vitro complementation test of Edgar and Wood; such isolated baseplates remain functional and can be converted to active phage in vitro on incubation with the necessary components. The products of the 3 genes interact with the baseplates sequentially, in the order 48:54;19.

Experiments with ts mutants in gene 19 indicate that this gene codes for the structural tail core subunit. The 48 and 54 gene products are apparently necessary to convert the baseplate to a substrate for core protein polymerization, and may be involved in the determination of the length of the core. Core protein cnly polymerizes in the presence of 48+ 54+ baseplates.

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