Sandbox GGC7

Triosephosphate isomerase (TPI or TIM) is a functionally and structurally well-known enzyme that play a crucial role in glycolytic and gluconeogenic metabolism. TPI interconverts dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P) ^[1]

Structure and Function

This crystal structure of trioseohosphate isomerase was isolated from Thermoplasma acidophilum, an archaeal species, and therefore was called TaTPI. contain four copies of TaTPI monomer in the asymmetric unit, comprising two homodimers. TaTPI is composed of 216 amino acid residues, which is shorter compare to other TPIs from bacterial and eukaryotic species. Each subunit of homotetramer forms a TIM barrel in which 8α helices alternate with 8β sheets to form backbone of the protein. Hydrophobic chains form the core enzyme whereas hydrophilic found near the ends of the barrel where exposed to solvent. Each subunit has it own active site and only active as a dimer. The active site includes conserved residues: Glu 137, His 89, Lys 9. The catalytic base is Gly 137. The oxyanion hole is formed between nitrogen of Lys 9 and of His 89 with O2 of G3P. The phosphate group of G3P forms hydrogen bonds with backbone nitrogen atoms of Gly143, Gly 175, Ala 196 and Ser 197 residues.

Disease

Relevance

Structural highlights