1SC1

Crystal structure of an active-site ligand-free form of the human caspase-1 C285A mutant

1SC1 の概要

• エントリーDOI: 10.2210/pdb1sc1/pdb
• 関連するPDBエントリー: 1SC3 1SC4
• 分子名称: Interleukin-1 beta convertase, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: ligand-free caspase-1, hydrolase
• 由来する生物種: Homo sapiens (human); 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 30131.98

構造登録者

Romanowski, M.J.,Scheer, J.M.,O'Brien, T.,McDowell, R.S. (登録日: 2004-02-11, 公開日: 2004-08-10, 最終更新日: 2023-08-23)

主引用文献

Romanowski, M.J.,Scheer, J.M.,O'Brien, T.,McDowell, R.S.
Crystal structures of a ligand-free and malonate-bound human caspase-1: implications for the mechanism of substrate binding.
Structure, 12:1361-1371, 2004

PubMed Abstract: Caspase-1, a mediator of the posttranslational processing of IL-1beta and IL-18, requires an aspartic acid in the P1 position of its substrates. The mechanisms of caspase-1 activation remain poorly understood despite numerous structures of the enzyme complexed with aspartate-based inhibitors. Here we report a crystal structure of ligand-free caspase-1 that displays dramatic rearrangements of loops defining the active site to generate a closed conformation that is incompatible with substrate binding. A structure of the enzyme complexed with malonate shows the protein in its open (active-site ligand-bound) conformation in which malonate reproduces the hydrogen bonding network observed in structures with covalent inhibitors. These results illustrate the essential function of the obligatory aspartate recognition element that opens the active site of caspase-1 to substrates and may be the determinant responsible for the conformational changes between ligand-free and -bound forms of the enzyme, and suggest a new approach for identifying novel aspartic acid mimetics.

PubMed: 15296730
DOI: 10.1016/j.str.2004.05.010

実験手法

X-RAY DIFFRACTION (2.6 Å)