2GUF

In meso crystal structure of the cobalamin transporter, BtuB

2GUF の概要

• エントリーDOI: 10.2210/pdb2guf/pdb
• 分子名称: Vitamin B12 transporter btuB, [(Z)-octadec-9-enyl] (2R)-2,3-bis(oxidanyl)propanoate, FORMIC ACID, ... (5 entities in total)
• 機能のキーワード: beta barrel, cubic mesophase, cobalamin, btub, colicin, transport protein
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cell outer membrane; Multi-pass membrane protein: P06129
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 70826.84

構造登録者

Caffrey, M.,Cherezov, V.,Yamashita, E.,Cramer, W.A. (登録日: 2006-04-29, 公開日: 2006-12-05, 最終更新日: 2024-02-14)

主引用文献

Cherezov, V.,Yamashita, E.,Liu, W.,Zhalnina, M.,Cramer, W.A.,Caffrey, M.
In Meso Structure of the Cobalamin Transporter, BtuB, at 1.95 A Resolution.
J.Mol.Biol., 364:716-734, 2006

PubMed Abstract: Crystals of the apo form of the vitamin B12 and colicin receptor, BtuB, that diffract to 1.95 A have been grown by the membrane-based in meso technique. The structure of the protein differs in several details from that of its counterpart grown by the more traditional, detergent-based (in surfo) method. Some of these differences include (i) the five N-terminal residues are resolved in meso, (ii) residues 57-62 in the hatch domain and residues 574-581 in loop 21-22 are disordered in meso and are ordered in surfo, (iii) residues 278-287 in loop 7-8 are resolved in meso, (iv) residues 324-331 in loop 9-10, 396-411 in loop 13-14, 442-458 in loop 15-16 and 526-541 in loop 19-20 have large differences in position between the two crystal forms, as have residues 86-96 in the hatch domain, and (v) the conformation of residues 6 and 7 in the Ton box (considered critical to signal transduction and substrate transport) are entirely different in the two structures. Importantly, the in meso orientation of residues 6 and 7 is similar to that of the vitamin B12-charged state. These data suggest that the "substrate-induced" 180 degrees -rotation of residues 6 and 7 reported in the literature may not be a unique signalling event. The extent to which these findings agree with structural, dynamic and functional insights gleaned from site-directed spin labelling and electron paramagnetic resonance measurements is evaluated. Packing in in meso grown crystals is dense and layered, consistent with the current model for crystallogenesis of membrane proteins in lipidic mesophases. Layered packing has been used to locate the transmembrane hydrophobic surface of the protein. Generally, this is consistent with tryptophan, tyrosine, lipid and CalphaB-factor distributions in the protein, and with predictions based on transfer free energy calculations.

PubMed: 17028020
DOI: 10.1016/j.jmb.2006.09.022

実験手法

X-RAY DIFFRACTION (1.95 Å)