5LJH

Crystal structure of human apo CRBP1/K40L mutant

5LJH の概要

• エントリーDOI: 10.2210/pdb5ljh/pdb
• 関連するPDBエントリー: 5LJB 5LJC 5LJD 5LJE 5LJG
• 分子名称: Retinol-binding protein 1, SODIUM ION (3 entities in total)
• 機能のキーワード: retinol, vitamin a, retinol-binding protein, rbp
• 由来する生物種: Homo sapiens (Human)
• 細胞内の位置: Cytoplasm: P09455
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 15878.15

構造登録者

Zanotti, G.,Vallese, F.,Berni, R.,Menozzi, I. (登録日: 2016-07-18, 公開日: 2017-01-18, 最終更新日: 2024-01-10)

主引用文献

Menozzi, I.,Vallese, F.,Polverini, E.,Folli, C.,Berni, R.,Zanotti, G.
Structural and molecular determinants affecting the interaction of retinol with human CRBP1.
J. Struct. Biol., 197:330-339, 2017

PubMed Abstract: Four cellular retinol-binding protein (CRBP) types (CRBP1,2,3,4) are encoded in the human genome. Here, we report on X-ray analyses of human apo- and holo-CRBP1, showing nearly identical structures, at variance with the results of a recent study on the same proteins containing a His-Tag, which appears to be responsible for a destabilizing effect on the apoprotein. The analysis of crystallographic B-factors for our structures indicates that the putative portal region, in particular α-helix-II, along with Arg58 and the E-F loop, is the most flexible part of both apo- and holoprotein, consistent with its role in ligand uptake and release. Fluorometric titrations of wild type and mutant forms of apo-CRBP1, coupled with X-ray analyses, provided insight into structural and molecular determinants for the interaction of retinol with CRBP1. An approximately stoichiometric binding of retinol to wild type apo-CRBP1 (Kd∼4.5nM), significantly lower binding affinity for both mutants Q108L (Kd∼65nM) and K40L (Kd∼70nM) and very low binding affinity for the double mutant Q108L/K40L (Kd∼250nM) were determined, respectively. Overall, our data indicate that the extensive apolar interactions between the ligand and hydrophobic residues lining the retinol binding cavity are sufficient to keep it in its position bound to CRBP1. However, polar interactions of the retinol hydroxyl end group with Gln108 and Lys40 play a key role to induce a high binding affinity and specificity for the interaction.

PubMed: 28057518
DOI: 10.1016/j.jsb.2016.12.012

実験手法

X-RAY DIFFRACTION (1.52 Å)