Crystallization and X-ray analysis of the T = 4 particle of hepatitis B capsid protein with an N-terminal extension.
Tan, W.S., McNae, I.W., Ho, K.L., Walkinshaw, M.D.(2007) Acta Crystallogr Sect F Struct Biol Cryst Commun 63: 642-647
- PubMed: 17671358 
- DOI: https://doi.org/10.1107/S1744309107033726
- Primary Citation of Related Structures:  
2QIJ - PubMed Abstract: 
Hepatitis 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.
Organizational Affiliation: 
Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.