View source for 7smi


==Crystal Structure of L-galactose dehydrogenase from Spinacia oleracea==
<StructureSection load='7smi' size='340' side='right'caption='[[7smi]], [[Resolution|resolution]] 1.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7smi]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Spinacia_oleracea Spinacia oleracea]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7SMI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7SMI FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.4&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7smi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7smi OCA], [https://pdbe.org/7smi PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7smi RCSB], [https://www.ebi.ac.uk/pdbsum/7smi PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7smi ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q6BDJ2_SPIOL Q6BDJ2_SPIOL] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In plants, it is well-known that ascorbic acid (vitamin C) can be synthesized via multiple metabolic pathways but there is still much to be learnt concerning their integration and control mechanisms. Furthermore, the structural biology of the component enzymes has been poorly exploited. Here we describe the first crystal structure for an L-galactose dehydrogenase (SoGDH from spinach), from the D-mannose/L-galactose (Smirnoff Wheeler) pathway which converts L-galactose into L-galactono-1,4-lactone. The kinetic parameters for the enzyme are similar to those from its homologue from camu-camu, a super-accumulator of vitamin C found in the Peruvian amazon. Both enzymes are monomers in solution, have a pH optimum of 7 and their activity is largely unaffected by high concentrations of ascorbic acid, suggesting the absence of a feedback mechanism acting via GDH. Previous reports may have been influenced by changes of the pH of the reaction medium as a function of ascorbic acid concentration. The structure of SoGDH is dominated by a (beta/alpha)8 barrel closely related to aldehyde-keto reductases (AKRs). The structure bound to NAD+ shows that the lack of Arg279 justifies its preference for NAD+ over NADP+, as employed by many AKRs. This favours the oxidation reaction which ultimately leads to ascorbic acid accumulation. When compared with other AKRs, residue substitutions at the C-terminal end of the barrel (Tyr185, Tyr61, Ser59 and Asp128) can be identified to be likely determinants of substrate specificity. The present work contributes towards a more comprehensive understanding of structure-function relationships in the enzymes involved in vitamin C synthesis.

Structural Characterization of L-Galactose Dehydrogenase: An Essential Enzyme for Vitamin C Biosynthesis.,Vargas JA, Leonardo DA, D'Muniz Pereira H, Lopes AR, Rodriguez HN, Cobos M, Marapara JL, Castro JC, Garratt RC Plant Cell Physiol. 2022 Jun 28. pii: 6619357. doi: 10.1093/pcp/pcac090. PMID:35765894<ref>PMID:35765894</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7smi" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Spinacia oleracea]]
[[Category: Cabrejos DAL]]
[[Category: Garratt RC]]
[[Category: Gomez JCC]]
[[Category: Pereira HM]]
[[Category: Santillan JAV]]