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Crystal Structure of the pre-assembly scaffolding protein gp7 from the double-stranded DNA bacteriophage phi29Crystal Structure of the pre-assembly scaffolding protein gp7 from the double-stranded DNA bacteriophage phi29
Structural highlights
FunctionSCAF_BPPH2 Scaffolding protein involved in the icosahedric procapsid assembly. Coassembles with the capsid proteins to form the procapsid, in which the scaffolding protein is found within the external shell of icosahedrally arranged capsid protein subunits. In a subsequent step the scaffolding protein molecules are released from the procapsid.[1] [2] [3] Publication Abstract from PubMedThree-dimensional structures of the double-stranded DNA bacteriophage phi29 scaffolding protein (gp7) before and after prohead assembly have been determined at resolutions of 2.2 and 2.8 A, respectively. Both structures are dimers that resemble arrows, with a four-helix bundle composing the arrowhead and a coiled coil forming the tail. The structural resemblance of gp7 to the yeast transcription factor GCN4 suggests a DNA-binding function that was confirmed by native gel electrophoresis. DNA binding to gp7 may have a role in mediating the structural transition from prohead to mature virus and scaffold release. A cryo-EM analysis indicates that gp7 is arranged inside the capsid as a series of concentric shells. The position of the higher density features in these shells correlates with the positions of hexamers in the equatorial region of the capsid, suggesting that gp7 may regulate formation of the prolate head through interactions with these hexamers. Bacteriophage phi29 scaffolding protein gp7 before and after prohead assembly.,Morais MC, Kanamaru S, Badasso MO, Koti JS, Owen BA, McMurray CT, Anderson DL, Rossmann MG Nat Struct Biol. 2003 Jul;10(7):572-6. PMID:12778115[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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