3QT4

Structure of digestive procathepsin L 3 of Tenebrio molitor larval midgut

3QT4 の概要

• エントリーDOI: 10.2210/pdb3qt4/pdb
• 関連するPDBエントリー: 3QJ3
• 分子名称: Cathepsin-L-like midgut cysteine proteinase, PHOSPHATE ION, TETRAETHYLENE GLYCOL, ... (5 entities in total)
• 機能のキーワード: hydrolase, cysteine proteinase, zymogen, intramolecular dissulphide bonds, insect larval midgut
• 由来する生物種: Tenebrio molitor (Yellow mealworm beetle)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 39324.98

構造登録者

Beton, D.,Guzzo, C.R.,Terra, W.R.,Farah, C.S. (登録日: 2011-02-22, 公開日: 2012-02-22, 最終更新日: 2024-11-06)

主引用文献

Beton, D.,Guzzo, C.R.,Ribeiro, A.F.,Farah, C.S.,Terra, W.R.
The 3D structure and function of digestive cathepsin L-like proteinases of Tenebrio molitor larval midgut.
Insect Biochem.Mol.Biol., 42:655-664, 2012

PubMed Abstract: Cathepsin L-like proteinases (CAL) are major digestive proteinases in the beetle Tenebrio molitor. Procathepsin Ls 2 (pCAL2) and 3 (pCAL3) were expressed as recombinant proteins in Escherichia coli, purified and activated under acidic conditions. Immunoblot analyses of different T. molitor larval tissues demonstrated that a polyclonal antibody to pCAL3 recognized pCAL3 and cathepsin L 3 (CAL3) only in the anterior two-thirds of midgut tissue and midgut luminal contents of T. molitor larvae. Furthermore, immunocytolocalization data indicated that pCAL3 occurs in secretory vesicles and microvilli in anterior midgut. Therefore CAL3, like cathepsin L 2 (CAL2), is a digestive enzyme secreted by T. molitor anterior midgut. CAL3 hydrolyses Z-FR-MCA and Z-RR-MCA (typical cathepsin substrates), whereas CAL2 hydrolyses only Z-FR-MCA. Active site mutants (pCAL2C25S and pCAL3C26S) were constructed by replacing the catalytic cysteine with serine to prevent autocatalytic processing. Recombinant pCAL2 and pCAL3 mutants (pCAL2C25S and pCAL3C26S) were prepared, crystallized and their 3D structures determined at 1.85 and 2.1 Å, respectively. While the overall structure of these enzymes is similar to other members of the papain superfamily, structural differences in the S2 subsite explain their substrate specificities. The data also supported models for CAL trafficking to lysosomes and to secretory vesicles to be discharged into midgut contents.

PubMed: 22659439
DOI: 10.1016/j.ibmb.2012.04.010

実験手法

X-RAY DIFFRACTION (2.11 Å)