Bacteriophage lambda preconnectors. Purification and structure.

J Kochan; J L Carrascosa; H Murialdo

doi:10.1016/0022-2836(84)90330-9

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Bacteriophage lambda preconnectors. Purification and structure.

J Kochan·J L Carrascosa·H Murialdo

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Abstract

The morphogenesis of bacteriophage lambda proheads is under the control of the four phage genes B, C, Nu3 and E, and the two Escherichia coli genes groEL and groES . It has been shown previously that extracts prepared from cells infected with a lambda C-E- mutant accumulate a gpB polymer, which behaves as a biologically active intermediate in prohead assembly. This gpB activity has been called a preconnector , as it is probably a precursor to the head-tail connector. We now report the partial purification of biologically active preconnectors and the characterization of its structure. In the electron microscope, preconnectors appear as donut -like structures composed of several subunits displaying radial symmetry. Optical filtration of periodic arrays of preconnectors showed that the structure has 12-fold rotational symmetry. Side views of the preconnector reveal that it resembles an asymmetrical dumbell . This information has been used to construct a three-dimensional model of the preconnector . The implications of this structure for prohead shape and function, and for DNA packaging are discussed.

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Bacteriophage lambda Electrophoresis, Polyacrylamide Gel Filtration Image Enhancement Microscopy, Electron Models, Molecular Viral Proteins Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.

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J Kochan, J L Carrascosa, H Murialdo. 1984-04-15. Bacteriophage lambda preconnectors. Purification and structure.. https://doi.org/10.1016/0022-2836(84)90330-9

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