8EWU

X-ray structure of the GDP-6-deoxy-4-keto-D-lyxo-heptose-4-reductase from Campylobacter jejuni HS:15

Summary for 8EWU

• Entry DOI: 10.2210/pdb8ewu/pdb
• Descriptor: GDP-L-fucose synthase, GUANOSINE-5'-DIPHOSPHATE, NADPH DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE, ... (5 entities in total)
• Functional Keywords: capsular polysaccharide, reductase, biosynthetic protein, oxidoreductase
• Biological source: Campylobacter jejuni
• Total number of polymer chains: 2
• Total formula weight: 88844.32

Authors

Thoden, J.B.,Xiang, D.F.,Ghosh, M.K.,Riegert, A.S.,Raushel, F.M.,Holden, H.M. (deposition date: 2022-10-24, release date: 2022-11-09, Last modification date: 2023-10-25)

Primary citation

Xiang, D.F.,Ghosh, M.K.,Riegert, A.S.,Thoden, J.B.,Holden, H.M.,Raushel, F.M.
Bifunctional Epimerase/Reductase Enzymes Facilitate the Modulation of 6-Deoxy-Heptoses Found in the Capsular Polysaccharides of Campylobacter jejuni.
Biochemistry, 62:134-144, 2023

PubMed Abstract: is a human pathogen and the leading cause of food poisoning in the United States and Europe. Surrounding the exterior surface of this bacterium is a capsular polysaccharide (CPS) that consists of a repeating sequence of common and unusual carbohydrate segments. At least 10 different heptose sugars have thus far been identified in the various strains of . The accepted biosynthetic pathway for the construction of the 6-deoxy-heptoses begins with the 4,6-dehydration of GDP-d--d--heptose by a dehydratase, followed by an epimerase that racemizes C3 and/or C5 of the product GDP-6-deoxy-4-keto-d--heptose. In the final step, a C4-reductase catalyzes the NADPH reduction of the resulting 4-keto product. However, in some strains and serotypes of , there are two separate C4-reductases with different product specificities in the gene cluster for CPS formation. Five pairs of these tandem C4-reductases were isolated, and the catalytic properties were ascertained. In four out of five cases, one of the two C4-reductases is able to catalyze the isomerization of C3 and C5 of GDP-6-deoxy-4-keto-d--heptose, in addition to the catalysis of the reduction of C4, thus bypassing the requirement for a separate C3/C5-isomerase. In each case, the 3'-end of the gene for the first C4-reductase contains a poly-G tract of 8-10 guanine residues that may be used to control the expression and/or catalytic activity of either C4-reductase. The three-dimensional structure of the C4-reductase from serotype HS:15, which only does a reduction of C4, was determined to 1.45 Å resolution in the presence of NADPH and GDP.

PubMed: 36534477
DOI: 10.1021/acs.biochem.2c00633

Experimental method

X-RAY DIFFRACTION (1.45 Å)