2FHN

Avidin related protein AVR4 (C122S, K109I mutant) in complex with BNA

2FHN の概要

• エントリーDOI: 10.2210/pdb2fhn/pdb
• 関連するPDBエントリー: 1Y52 1Y53 2FHL
• 分子名称: Avidin-related protein 4/5, 5-(2-OXO-HEXAHYDRO-THIENO[3,4-D]IMIDAZOL-6-YL)-PENTANOIC ACID (4-NITRO-PHENYL)-AMIDE, FORMIC ACID, ... (4 entities in total)
• 機能のキーワード: avidin, streptavidin, avr4, high affinity, hydrolytic activity, sugar binding protein
• 由来する生物種: Gallus gallus (chicken)
• 細胞内の位置: Secreted (Potential): P56734
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 29290.84

構造登録者

Livnah, O.,Prizant, M. (登録日: 2005-12-26, 公開日: 2006-03-21, 最終更新日: 2024-11-13)

主引用文献

Prizant, M.,Eisenberg-Domovich, Y.,Hytonen, V.P.,Kulomaa, M.S.,Wilchek, M.,Bayer, E.A.,Livnah, O.
Factors dictating the pseudocatalytic efficiency of avidins
J.Mol.Biol., 358:754-763, 2006

PubMed Abstract: The hydrolysis of biotinyl p-nitrophenyl ester (BNP) by a series of avidin derivatives was examined. Surprisingly, a hyperthermostable avidin-related protein (AVR4) was shown to display extraordinary yet puzzling hydrolytic activity. In order to evaluate the molecular determinants that contribute to the reaction, the crystal structure of AVR4 was compared with those of avidin, streptavidin and key mutants of the two proteins in complex with biotinyl p-nitroanilide (BNA), the inert amide analogue of BNP. The structures revealed that a critical lysine residue contributes to the hydrolysis of BNP by avidin but has only a minor contribution to the AVR4-mediated reaction. Indeed, the respective rates of hydrolysis among the different avidins reflect several molecular parameters, including binding-site architecture, the availability of the ligand to solvent and the conformation of the ligand and consequent susceptibility to efficient nucleophilic attack. In avidin, the interaction of BNP with Lys111 and disorder of the L3,4 loop (and consequent solvent availability) together comprise the major driving force behind the hydrolysis, whereas in AVR4 the status of the ligand (the pseudo-substrate) is a major distinguishing feature. In the latter protein, a unique conformation of the L3,4 loop restrains the pseudo-substrate, thereby exposing the carbonyl carbon atom to nucleophilic attack. In addition, due to its conformation, the pseudo-substrate in the AVR4 complex cannot interact with the conserved lysine analogue (Lys109); instead, this function is superseded by polar interactions with Arg112. The results demonstrate that, in highly similar proteins, different residues can perform the same function and that subtle differences in the active-site architecture of such proteins can result in alternative modes of reaction.

PubMed: 16546211
DOI: 10.1016/j.jmb.2006.02.044

実験手法

X-RAY DIFFRACTION (1.3 Å)