1jn0
From Proteopedia
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| , resolution 3.00Å | |||||||
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| Ligands: | , | ||||||
| Activity: | Glyceraldehyde-3-phosphate dehydrogenase (NADP(+)) (phosphorylating), with EC number 1.2.1.13 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of the non-regulatory A4 isoform of spinach chloroplast glyceraldehyde-3-phosphate dehydrogenase complexed with NADP
Overview
Here, we report the first crystal structure of a photosynthetic glyceraldehyde-3-phosphate dehydrogenase (GAPDH) complexed with NADP. The enzyme, purified from spinach chloroplasts, is constituted of a single type of subunit (A) arranged in homotetramers. It shows non-regulated NADP-dependent and NAD-dependent activities, with a preference for NADP. The structure has been solved to 3.0 A resolution by molecular replacement. The crystals belong to space group C222 with three monomers in the asymmetric unit. One of the three monomers generates a tetramer using the space group 222 point symmetry and a very similar tetramer is generated by the other two monomers, related by a non-crystallographic symmetry, using a crystallographic 2-fold axis.The protein reveals a large structural homology with known GAPDHs both in the cofactor-binding domain and in regions of the catalytic domain. Like all other GAPDHs investigated so far, the A(4)-GAPDH belongs to the Rossmann fold family of dehydrogenases. However, unlike most dehydrogenases of this family, the adenosine 2'-phosphate group of NADP does not form a salt-bridge with any positively charged residue in its surroundings, being instead set in place by hydrogen bonds with a threonine residue belonging to the Rossmann fold and a serine residue located in the S-loop of a symmetry-related monomer. While increasing our knowledge of an important photosynthetic enzyme, these results contribute to a general understanding of NADP versus NAD recognition in pyridine nucleotide-dependent enzymes.Although the overall structure of A(4)-GAPDH is similar to that of the cytosolic GAPDH from bacteria and eukaryotes, the chloroplast tetramer is peculiar, in that it can actually be considered a dimer of dimers, since monomers are bound in pairs by a disulphide bridge formed across Cys200 residues. This bridge is not found in other cytosolic or chloroplast GAPDHs from animals, bacteria, or plants other than spinach.
About this Structure
1JN0 is a Single protein structure of sequence from Spinacia oleracea. Full crystallographic information is available from OCA.
Reference
Crystal structure of the non-regulatory A(4 )isoform of spinach chloroplast glyceraldehyde-3-phosphate dehydrogenase complexed with NADP., Fermani S, Ripamonti A, Sabatino P, Zanotti G, Scagliarini S, Sparla F, Trost P, Pupillo P, J Mol Biol. 2001 Nov 30;314(3):527-42. PMID:11846565
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