2qij
From Proteopedia
Hepatitis B Capsid Protein with an N-terminal extension modelled into 8.9 A data.
Structural highlights
Function[CAPSD_HBVD1] Self assembles to form an icosahedral capsid. Most capsid appear to be large particles with a icosahedral symmetry of T=4 and consist of 240 copies of capsid protein, though a fraction forms smaller T=3 particles consisting of 180 capsid proteins. Entering capsid are transported along microtubules to the nucleus. Phosphorylation of the capsid is thought to induce exposure of nuclear localization signal in the C-terminal portion of the capsid protein that allows binding to the nuclear pore complex via the importin (karyopherin-) alpha and beta. Capsids are imported in intact form through the nuclear pore into the nuclear basket, where it probably binds NUP153. Only capsids that contain the mature viral genome can release the viral DNA and capsid protein into the nucleoplasm. Immature capsids get stucked in the basket. Capsids encapsulate the pre-genomic RNA and the P protein. Pre-genomic RNA is reverse transcribed into DNA while the capsid is still in the cytoplasm. The capsid can then either be directed to the nucleus, providing more genome for transcription, or bud through the endoplasmic reticulum to provide new virions (By similarity).[1] Encapsidates hepatitis delta genome (By similarity).[2] 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 PubMedHepatitis B core (HBc) particles have been extensively exploited as carriers for foreign immunological epitopes in the development of multicomponent vaccines and diagnostic reagents. Crystals of the T = 4 HBc particle were grown in PEG 20,000, ammonium sulfate and various types of alcohols. A temperature jump from 277 or 283 to 290 K was found to enhance crystal growth. A crystal grown using MPD as a cryoprotectant diffracted X-rays to 7.7 A resolution and data were collected to 99.6% completeness at 8.9 A. The crystal belongs to space group P2(1)2(1)2(1), with unit-cell parameters a = 352.3, b = 465.5, c = 645.0 A. The electron-density map reveals a protrusion that is consistent with the N-terminus extending out from the surface of the capsid. The structure presented here supports the idea that N-terminal insertions can be exploited in the development of diagnostic reagents, multicomponent vaccines and delivery vehicles into mammalian cells. Crystallization and X-ray analysis of the T = 4 particle of hepatitis B capsid protein with an N-terminal extension.,Tan WS, McNae IW, Ho KL, Walkinshaw MD Acta Crystallogr Sect F Struct Biol Cryst Commun. 2007 Aug 1;63(Pt, 8):642-7. Epub 2007 Jul 21. PMID:17671358[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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