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NMR structure of the gpu tail protein from lambda bacteriophage
Structural highlights
FunctionTTTP_LAMBD Plays an essential role in tail assembly by capping the rapidly polymerizing tail once it has reached its requisite length and serving as the interaction surface for the completion protein.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedDuring the late stages of lambda bacteriophage assembly, the protein gpU terminates tail polymerization and participates at the interface between the mature capsid and tail components. When it engages the lambda tail, gpU undergoes a monomer-hexamer transition to achieve its biologically active form. Towards understanding how gpU participates in multiple protein-protein interactions, we have solved the structure of gpU in its monomeric state using NMR methods. The structure reveals a mixed alpha/beta motif with several dynamic loops at the periphery. Addition of 20 mM MgCl(2) is known to oligomerize gpU in the absence of its protein partners. Multiple image analysis of electron micrographs revealed ring-like structures of magnesium ion saturated gpU with a 30 A pore, consistent with its function as a portal for the passage of viral DNA into the host bacterium. The ability of magnesium ions to promote oligomerization was lost when substitutions were made at a cluster of acidic amino acids in the vicinity of helix alpha2 and the beta1-beta2 loop. Furthermore, substitutions at these sites abolished the biological activity of gpU. The NMR structure of the gpU tail-terminator protein from bacteriophage lambda: identification of sites contributing to Mg(II)-mediated oligomerization and biological function.,Edmonds L, Liu A, Kwan JJ, Avanessy A, Caracoglia M, Yang I, Maxwell KL, Rubenstein J, Davidson AR, Donaldson LW J Mol Biol. 2007 Jan 5;365(1):175-86. Epub 2006 Sep 29. PMID:17056065[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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