3TNX

Structure of the precursor of a thermostable variant of papain at 2.6 Angstroem resolution

3TNX の概要

• エントリーDOI: 10.2210/pdb3tnx/pdb
• 関連するPDBエントリー: 9PAP
• 分子名称: Papain, CHLORIDE ION (3 entities in total)
• 機能のキーワード: hydrolase, cytoplasm for recombinant expression
• 由来する生物種: Carica papaya (mamon)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 82170.59

構造登録者

Roy, S.,Choudhury, D.,Dattagupta, J.K.,Biswas, S. (登録日: 2011-09-02, 公開日: 2012-09-12, 最終更新日: 2024-10-30)

主引用文献

Roy, S.,Choudhury, D.,Aich, P.,Dattagupta, J.K.,Biswas, S.
The structure of a thermostable mutant of pro-papain reveals its activation mechanism
Acta Crystallogr.,Sect.D, 68:1591-1603, 2012

PubMed Abstract: Papain is the archetype of a broad class of cysteine proteases (clan C1A) that contain a pro-peptide in the zymogen form which is required for correct folding and spatio-temporal regulation of proteolytic activity in the initial stages after expression. This study reports the X-ray structure of the zymogen of a thermostable mutant of papain at 2.6 Å resolution. The overall structure, in particular that of the mature part of the protease, is similar to those of other members of the family. The structure provides an explanation for the molecular basis of the maintenance of latency of the proteolytic activity of the zymogen by its pro-segment at neutral pH. The structural analysis, together with biochemical and biophysical studies, demonstrated that the pro-segment of the zymogen undergoes a rearrangement in the form of a structural loosening at acidic pH which triggers the proteolytic activation cascade. This study further explains the bimolecular stepwise autocatalytic activation mechanism by limited proteolysis of the zymogen of papain at the molecular level. The possible factors responsible for the higher thermal stability of the papain mutant have also been analyzed.

PubMed: 23151624
DOI: 10.1107/S0907444912038607

実験手法

X-RAY DIFFRACTION (2.62 Å)