1II2

Crystal Structure of Phosphoenolpyruvate Carboxykinase (PEPCK) from Trypanosoma cruzi

1II2 の概要

• エントリーDOI: 10.2210/pdb1ii2/pdb
• 分子名称: PHOSPHOENOLPYRUVATE CARBOXYKINASE, SULFATE ION (3 entities in total)
• 機能のキーワード: phosphate binding loop, lyase
• 由来する生物種: Trypanosoma cruzi
• 細胞内の位置: Glycosome (By similarity): P51058
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 117824.67

構造登録者

Trapani, S.,Linss, J.,Goldenberg, S.,Fischer, H.,Craievich, A.F.,Oliva, G. (登録日: 2001-04-20, 公開日: 2001-11-21, 最終更新日: 2023-08-16)

主引用文献

Trapani, S.,Linss, J.,Goldenberg, S.,Fischer, H.,Craievich, A.F.,Oliva, G.
Crystal structure of the dimeric phosphoenolpyruvate carboxykinase (PEPCK) from Trypanosoma cruzi at 2 A resolution.
J.Mol.Biol., 313:1059-1072, 2001

PubMed Abstract: ATP-dependent phosphoenolpyruvate carboxykinase (PEPCK) (ATP: oxaloacetate carboxylyase (transphosphorylating), EC 4.1.1.49) is a key enzyme involved in the catabolism of glucose and amino acids in the parasite Trypanosoma cruzi, the causative agent of Chagas' disease. Due to the significant differences in the amino acid sequence and substrate specificity of the human enzyme (PEPCK (GTP-dependent), EC 4.1.1.32), the parasite enzyme has been considered a good target for the development of new anti-chagasic drugs. We have solved the crystal structure of the recombinant PEPCK of T. cruzi up to 2.0 A resolution, characterised the dimeric organisation of the enzyme by solution small angle X-ray scattering (SAXS) and compared the enzyme structure with the known crystal structure of the monomeric PEPCK from Escherichia coli. The dimeric structure possesses 2-fold symmetry, with each monomer sharing a high degree of structural similarity with the monomeric structure of the E. coli PEPCK. Each monomer folds into two complex mixed alpha/beta domains, with the active site located in a deep cleft between the domains. The two active sites in the dimer are far apart from each other, in an arrangement that seems to permit an independent access of the substrates to the two active sites. All residues of the E. coli PEPCK structure that had been found to interact with substrates and metal cofactors have been found conserved and in a substantially equivalent spatial disposition in the T. cruzi PEPCK structure. No substrate or metal ion was present in the crystal structure. A sulphate ion from the crystallisation medium has been found bound to the active site. Solution SAXS data suggest that, in solutions with lower sulphate concentration than that used for the crystallisation experiments, the actual enzyme conformation may be slightly different from its conformation in the crystal structure. This could be due to a conformational transition upon sulphate binding, similar to the ATP-induced transition observed in the E. coli PEPCK, or to crystal packing effects. The present structure of the T. cruzi PEPCK will provide a good basis for the modelling of new anti-chagasic drug leads.

PubMed: 11700062
DOI: 10.1006/jmbi.2001.5093

実験手法

X-RAY DIFFRACTION (2 Å)