1QRR

CRYSTAL STRUCTURE OF SQD1 PROTEIN COMPLEX WITH NAD AND UDP-GLUCOSE

Summary for 1QRR

• Entry DOI: 10.2210/pdb1qrr/pdb
• Descriptor: sulfolipid biosynthesis (SQD1) PROTEIN, SULFATE ION, NICOTINAMIDE-ADENINE-DINUCLEOTIDE, ... (5 entities in total)
• Functional Keywords: rossmann fold, short hydrogen bonds, sdr homolog, isomerase
• Biological source: Arabidopsis thaliana (thale cress)
• Cellular location: Plastid, chloroplast : O48917
• Total number of polymer chains: 1
• Total formula weight: 45786.24

Authors

Mulichak, A.M.,Theisen, M.J.,Essigmann, B.,Benning, C.,Garavito, R.M. (deposition date: 1999-06-15, release date: 1999-11-10, Last modification date: 2024-02-14)

Primary citation

Mulichak, A.M.,Theisen, M.J.,Essigmann, B.,Benning, C.,Garavito, R.M.
Crystal structure of SQD1, an enzyme involved in the biosynthesis of the plant sulfolipid headgroup donor UDP-sulfoquinovose.
Proc.Natl.Acad.Sci.USA, 96:13097-13102, 1999

PubMed Abstract: The SQD1 enzyme is believed to be involved in the biosynthesis of the sulfoquinovosyl headgroup of plant sulfolipids, catalyzing the transfer of SO(3)(-) to UDP-glucose. We have determined the structure of the complex of SQD1 from Arabidopsis thaliana with NAD(+) and the putative substrate UDP-glucose at 1.6-A resolution. Both bound ligands are completely buried within the binding cleft, along with an internal solvent cavity which is the likely binding site for the, as yet, unidentified sulfur-donor substrate. SQD1 is a member of the short-chain dehydrogenase/reductase (SDR) family of enzymes, and its structure shows a conservation of the SDR catalytic residues. Among several highly conserved catalytic residues, Thr-145 forms unusually short hydrogen bonds with both susceptible hydroxyls of UDP-glucose. A His side chain may also be catalytically important in the sulfonation.

PubMed: 10557279
DOI: 10.1073/pnas.96.23.13097

Experimental method

X-RAY DIFFRACTION (1.6 Å)