1O0E

1.9 Angstrom Crystal Structure of a plant cysteine protease Ervatamin C

1O0E の概要

• エントリーDOI: 10.2210/pdb1o0e/pdb
• 分子名称: Ervatamin C, THIOSULFATE (3 entities in total)
• 機能のキーワード: plant cysteine protease, two domain, stable at ph 2-12, hydrolase
• 由来する生物種: Tabernaemontana divaricata
• 細胞内の位置: Secreted: P83654
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 45257.18

構造登録者

Thakurta, P.G.,Chakrabarti, C.,Biswas, S.,Dattagupta, J.K. (登録日: 2003-02-21, 公開日: 2004-03-02, 最終更新日: 2024-10-09)

主引用文献

Thakurta, P.G.,Biswas, S.,Chakrabarti, C.,Sundd, M.,Jagannadham, M.V.,Dattagupta, J.K.
Structural Basis of the Unusual Stability and Substrate Specificity of Ervatamin C, a Plant Cysteine Protease from Ervatamia coronaria
Biochemistry, 43:1532-1540, 2004

PubMed Abstract: Ervatamin C is an unusually stable cysteine protease from the medicinal plant Ervatamia coronaria belonging to the papain family. Though it cleaves denatured natural proteins with high specific activity, its activity toward some small synthetic substrates is found to be insignificant. The three-dimensional structure and amino acid sequence of the protein have been determined from X-ray diffraction data at 1.9 A (R = 17.7% and R(free) = 19.0%). The overall structure of ervatamin C is similar to those of other homologous cysteine proteases of the family, folding into two distinct left and right domains separated by an active site cleft. However, substitution of a few amino acid residues, which are conserved in the other members of the family, has been observed in both the domains and also at the region of the interdomain cleft. Consequently, the number of intra- and interdomain hydrogen-bonding interactions is enhanced in the structure of ervatamin C. Moreover, a unique disulfide bond has been identified in the right domain of the structure, in addition to the three conserved disulfide bridges present in the papain family. All these factors contribute to an increase in the stability of ervatamin C. In this enzyme, the nature of the S2 subsite, which is the primary determinant of specificity of these proteases, is similar to that of papain, but at the S3 subsite, Ala67 replaces an aromatic residue, and has the effect of eliminating sufficient hydrophobic interactions required for S3-P3 stabilization. This provides the possible explanation for the lower activity of ervatamin C toward the small substrate/inhibitor. This substitution, however, does not affect the binding of denatured natural protein substrates to the enzyme significantly, as there exist a number of additional interactions at the enzyme-substrate interface outside the active site cleft.

PubMed: 14769029
DOI: 10.1021/bi0357659

実験手法

X-RAY DIFFRACTION (1.9 Å)