1IJG

Structure of the Bacteriophage phi29 Head-Tail Connector Protein

1IJG の概要

• エントリーDOI: 10.2210/pdb1ijg/pdb
• 関連するPDBエントリー: 1FOQ 1FOU
• 分子名称: UPPER COLLAR PROTEIN (2 entities in total)
• 機能のキーワード: alpha-helical bundle, rna binding motif, viral protein
• 由来する生物種: Bacillus phage phi29
• タンパク質・核酸の鎖数: 12
• 化学式量合計: 431007.52

構造登録者

Simpson, A.A.,Leiman, P.G.,Tao, Y.,He, Y.,Badasso, M.,Jardine, P.J.,Anderson, D.L.,Rossmann, M.G. (登録日: 2001-04-26, 公開日: 2001-05-09, 最終更新日: 2023-08-16)

主引用文献

Simpson, A.A.,Leiman, P.G.,Tao, Y.,He, Y.,Badasso, M.O.,Jardine, P.J.,Anderson, D.L.,Rossmann, M.G.
Structure determination of the head-tail connector of bacteriophage phi29.
Acta Crystallogr.,Sect.D, 57:1260-1269, 2001

PubMed Abstract: The head-tail connector of bacteriophage phi29 is composed of 12 36 kDa subunits with 12-fold symmetry. It is the central component of a rotary motor that packages the genomic dsDNA into preformed proheads. This motor consists of the head-tail connector, surrounded by a phi29-encoded, 174-base, RNA and a viral ATPase protein, both of which have fivefold symmetry in three-dimensional cryo-electron microscopy reconstructions. DNA is translocated into the prohead through a 36 A diameter pore in the center of the connector, where the DNA takes the role of a motor spindle. The helical nature of the DNA allows the rotational action of the connector to be transformed into a linear translation of the DNA. The crystal structure determination of connector crystals in space group C2 was initiated by molecular replacement, using an approximately 20 A resolution model derived from cryo-electron microscopy. The model phases were extended to 3.5 A resolution using 12-fold non-crystallographic symmetry averaging and solvent flattening. Although this electron density was not interpretable, the phases were adequate to locate the position of 24 mercury sites of a thimerosal heavy-atom derivative. The resultant 3.2 A single isomorphous replacement phases were improved using density modification, producing an interpretable electron-density map. The crystallographically refined structure was used as a molecular-replacement model to solve the structures of two other crystal forms of the connector molecule. One of these was in the same space group and almost isomorphous, whereas the other was in space group P2(1)2(1)2. The structural differences between the oligomeric connector molecules in the three crystal forms and between different monomers within each crystal show that the structure is relatively flexible, particularly in the protruding domain at the wide end of the connector. This domain probably acts as a bearing, allowing the connector to rotate within the pentagonal portal of the prohead during DNA packaging.

PubMed: 11526317
DOI: 10.1107/S0907444901010435

実験手法

X-RAY DIFFRACTION (2.9 Å)