2Q3N

Agglutinin from Abrus Precatorius (APA-I)

「2AMZ」から置き換えられました

2Q3N の概要

• エントリーDOI: 10.2210/pdb2q3n/pdb
• 分子名称: Agglutinin-1 A chain, Agglutinin-1 B chain, 2-acetamido-2-deoxy-beta-D-glucopyranose (3 entities in total)
• 機能のキーワード: ribosome-inactivating protein, immunotoxin, agglutinin abrin, plant protein
• 由来する生物種: Abrus precatorius (Indian licorice); 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 59579.08

構造登録者

Bagaria, A.,Surendranath, K.,Ramagopal, U.A.,Ramakumar, S.,Karande, A.A. (登録日: 2007-05-30, 公開日: 2007-06-26, 最終更新日: 2024-10-30)

主引用文献

Bagaria, A.,Surendranath, K.,Ramagopal, U.A.,Ramakumar, S.,Karande, A.A.
Structure-Function Analysis and Insights into the Reduced Toxicity of Abrus precatorius Agglutinin I in Relation to Abrin.
J.Biol.Chem., 281:34465-34474, 2006

PubMed Abstract: Abrin and agglutinin-I from the seeds of Abrus precatorius are type II ribosome-inactivating proteins that inhibit protein synthesis in eukaryotic cells. The two toxins share a high degree of sequence similarity; however, agglutinin-I is weaker in its activity. We compared the kinetics of protein synthesis inhibition by abrin and agglutinin-I in two different cell lines and found that approximately 200-2000-fold higher concentration of agglutinin-I is needed for the same degree of inhibition. Like abrin, agglutinin-I also induced apoptosis in the cells by triggering the intrinsic mitochondrial pathway, although at higher concentrations as compared with abrin. The reason for the decreased toxicity of agglutinin-I became apparent on the analysis of the crystal structure of agglutinin-I obtained by us in comparison with that of the reported structure of abrin. The overall protein folding of agglutinin-I is similar to that of abrin-a with a single disulfide bond holding the toxic A subunit and the lectin-like B-subunit together, constituting a heterodimer. However, there are significant differences in the secondary structural elements, mostly in the A chain. The substitution of Asn-200 in abrin-a with Pro-199 in agglutinin-I seems to be a major cause for the decreased toxicity of agglutinin-I. This perhaps is not a consequence of any kink formation by a proline residue in the helical segment, as reported by others earlier, but due to fewer interactions that proline can possibly have with the bound substrate.

PubMed: 16772301
DOI: 10.1074/jbc.M601777200

実験手法

X-RAY DIFFRACTION (3.5 Å)