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1jn0
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(New page: 200px<br /><applet load="1jn0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jn0, resolution 3.00Å" /> '''Crystal structure of...)
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Revision as of 16:16, 20 November 2007
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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 with SO4 and NDP as ligands. Active as Glyceraldehyde-3-phosphate dehydrogenase (NADP(+)) (phosphorylating), with EC number 1.2.1.13 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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