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 Å 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 A4-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 A4-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. © 2001 Academic Press.

Fermani S., Ripamonti A., Sabatino P., Zanotti G., Scagliarini S., Sparla F., et al. (2001). Crystal structure of the non-regulatory A4 isoform of spinach chloroplast glyceraldehyde-3-phosphate dehydrogenase complexed with NADP. JOURNAL OF MOLECULAR BIOLOGY, 314(3), 527-542 [10.1006/jmbi.2001.5172].

Crystal structure of the non-regulatory A4 isoform of spinach chloroplast glyceraldehyde-3-phosphate dehydrogenase complexed with NADP

Fermani S.;Ripamonti A.;Sabatino P.;Scagliarini S.;Sparla F.;Trost P.;Pupillo P.
2001

Abstract

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 Å 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 A4-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 A4-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. © 2001 Academic Press.
2001
Fermani S., Ripamonti A., Sabatino P., Zanotti G., Scagliarini S., Sparla F., et al. (2001). Crystal structure of the non-regulatory A4 isoform of spinach chloroplast glyceraldehyde-3-phosphate dehydrogenase complexed with NADP. JOURNAL OF MOLECULAR BIOLOGY, 314(3), 527-542 [10.1006/jmbi.2001.5172].
Fermani S.; Ripamonti A.; Sabatino P.; Zanotti G.; Scagliarini S.; Sparla F.; Trost P.; Pupillo P.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/917270
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