1gav
From Proteopedia
BACTERIOPHAGE GA PROTEIN CAPSID
Structural highlights
FunctionCAPSD_BPGA Capsid protein self-assembles to form an icosahedral capsid with a T=3 symmetry, about 26 nm in diameter, and consisting of 89 capsid proteins dimers (178 capsid proteins). Involved in viral genome encapsidation through the interaction between a capsid protein dimer and the multiple packaging signals present in the RNA genome. The capsid contains also 1 copy of the A2 maturation protein.[UniProtKB:P03612] Acts as a translational repressor of viral replicase synthesis late in infection. This latter function is the result of capsid protein interaction with an RNA hairpin which contains the replicase ribosome-binding site.[UniProtKB:P03612] Publication Abstract from PubMedThe three-dimensional structure of the small T=3 RNA bacteriophage GA has been determined at 3.4 A resolution. The structure was solved by molecular replacement, using the phage MS2 as an initial model. A comparison of the protein shells of the four related phages GA, MS2, fr and Qbeta was carried out in order to define structural features of particular importance for their assembly and specific RNA interaction. A high degree of similarity was found in the RNA binding sites, whereas larger structural differences are located in the loop regions of the coat proteins, especially in the FG loops forming 5-fold and quasi-6-fold contacts. The overall arrangement of the protein subunits in the shells of these phages is very similar, although the details of the interactions differ. The few conserved interactions are suggested to govern the subunit packing during assembly. The crystal structure of bacteriophage GA and a comparison of bacteriophages belonging to the major groups of Escherichia coli leviviruses.,Tars K, Bundule M, Fridborg K, Liljas L J Mol Biol. 1997 Sep 5;271(5):759-73. PMID:9299325[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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