7via
From Proteopedia
Focused refinement of asymmetric unit of bacteriophage lambda procapsid at 3.88 Angstrom
Structural highlights
Function[CAPSD_LAMBD] Assembles to form an icosahedral capsid with a T=7 symmetry. The icosahedral capsid is about 60 nm in diameter and composed of 415 major capsid proteins. The assembly is primed by the interaction between capsid assembly protease and portal dodecamer, and major capsid proteins assemble cooperatively to form the procapsid with the help of capsid scaffolding protein. Major capsid protein forms hexons and pentons of the icosahedron. Viral genomic DNA is packaged into the procapsid through the portal vertex (By similarity). The packaging triggers a dramatic reconfiguration of the capsid shell, expanding from roughly 50nm to 60nm while the capsid thickness decreases. The capsid decoration protein binds the expanded capsid and stabilizes it.[HAMAP-Rule:MF_04133][1] [2] [3] Publication Abstract from PubMedBacteriophage lambda is an excellent model system for studying capsid assembly of double-stranded DNA (dsDNA) bacteriophages, some dsDNA archaeal viruses, and herpesviruses. HK97 fold coat proteins initially assemble into a precursor capsid (procapsid) and subsequent genome packaging triggers morphological expansion of the shell. An auxiliary protein is required to stabilize the expanded capsid structure. To investigate the capsid maturation mechanism, we determined the cryo-electron microscopy structures of the bacteriophage lambda procapsid and mature capsid at 3.88 A and 3.76 A resolution, respectively. Besides primarily rigid body movements of common features of the major capsid protein gpE, large-scale structural rearrangements of other domains occur simultaneously. Assembly of intercapsomers within the procapsid is facilitated by layer-stacking effects at 3-fold vertices. Upon conformational expansion of the capsid shell, the missing top layer is fulfilled by cementing the gpD protein against the internal pressure of DNA packaging. Our structures illuminate the assembly mechanisms of dsDNA viruses. Structural basis of bacteriophage lambda capsid maturation.,Wang C, Zeng J, Wang J Structure. 2022 Jan 4. pii: S0969-2126(21)00461-5. doi:, 10.1016/j.str.2021.12.009. PMID:35026161[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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