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A touch of glue to complete bacteriophage assembly: the tail‐to‐head joining protein ( THJP ) family
Author(s) -
Auzat Isabelle,
Petitpas Isabelle,
Lurz Rudi,
Weise Frank,
Tavares Paulo
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12526
Subject(s) - biology , bacteriophage , head (geology) , glue , genetics , family member , genealogy , gene , engineering , escherichia coli , mechanical engineering , history , paleontology
Summary Bacteriophage SPP 1 is a nanomachine built to infect the bacterium B acillus subtilis . The phage particle is composed of an icosahedric capsid, which contains the viral DNA , and a long non‐contractile tail. Capsids and tails are produced in infected cells by two distinct morphogenetic pathways. Characterization of the suppressor‐sensitive mutant SPP 1 sus82 showed that it produces DNA ‐filled capsids and tails but is unable to assemble complete virions. Its purified tails have a normal length but lack a narrow ring that tapers the tail end found at the tail‐to‐head interface. The mutant is defective in production of gp17. The gp17 ring is exposed in free tails competent for viral assembly but becomes shielded in the final virion structure. Recombinant gp17 is active in an in vitro assay to stick together capsids and tails present in extracts of SPP 1 sus82 ‐infected cells, leading to formation of infectious particles. Gp17 thus plays a fundamental role in the tail‐to‐head joining reaction, the ultimate step of virus particle assembly. This is the conserved function of gp17 and its structurally related proteins like lambda gpU . This family of proteins can also provide fidelity to termination of the tail tube elongation reaction in a subset of phages including coliphage lambda.