8fql
From Proteopedia
Portal vertex of HK97 phage
Structural highlights
FunctionPORTL_BPHK7 Forms the portal vertex of the capsid. This portal plays critical roles in head assembly, genome packaging, neck/tail attachment, and genome ejection. The portal protein multimerizes as a single ring-shaped homododecamer arranged around a central channel. Binds to the terminase subunits to form the packaging machine.[UniProtKB:P25480] Publication Abstract from PubMedTailed bacteriophages and herpesviruses use a transient scaffold to assemble icosahedral capsids with hexameric capsomers on the faces and pentameric capsomers at all but one vertex where a 12-fold portal is thought to nucleate the assembly. How does the scaffold orchestrate this step? We have determined the portal vertex structure of the bacteriophage HK97 procapsid, where the scaffold is a domain of the major capsid protein. The scaffold forms rigid helix-turn-strand structures on the interior surfaces of all capsomers and is further stabilized around the portal, forming trimeric coiled-coil towers, two per surrounding capsomer. These 10 towers bind identically to 10 of 12 portal subunits, adopting a pseudo-12-fold organization that explains how the symmetry mismatch is managed at this early step. A symmetry mismatch unraveled: How phage HK97 scaffold flexibly accommodates a 12-fold pore at a 5-fold viral capsid vertex.,Huet A, Oh B, Maurer J, Duda RL, Conway JF Sci Adv. 2023 Jun 16;9(24):eadg8868. doi: 10.1126/sciadv.adg8868. Epub 2023 Jun , 16. PMID:37327331[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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