Crystal structure of glucuronic acid dehydrogeanse from Chromohalobacter salexigens

Biochemical characterization of uronate dehydrogenases from three Pseudomonads, Chromohalobacter salixigens, and Polaromonas naphthalenivorans

“…Induction, discovery, purification and characterization of UDH enzyme of unknown amino acid sequence from Pseudomonas syringae was first reported in 1959 and intermittently thereafter [8,15,16], while recombinant UDH from this organism, identical to that reported on here, has previously been partially characterized [17]. X-ray crystal structures have been solved for UDH from both Chromohalobacter salixigens (pdb code 3AY3) [1,18] and Agrobacterium tumefaciens (pdb code 3RFT) [19]. Reported applications of UDH include development of spectrophotometric single-and coupled-enzyme assays for the quantitation of uronate glycosides and uronic acids [20,21], metabolic engineering of the fungi Hypocrea jecorina and Aspergillus niger [22] and Saccharomyces cerevisiae [23] for conversion of GalUA to galactaric acid, and creation of a synthetic metabolic pathway not observed in nature for the (in vivo) conversion of glucose to glucaric acid in E. coli [24].…”

“…2). Active site catalytic residues in other SDR's [25,29], previously shown by Ahn and coworkers to be conserved in CsUDH [1], are also strictly conserved (Fig. 2); these include (CsUDH numbering) a catalytic triad Tyr136-x-x-x-Lys140 and Ser111.…”

“…Amino acid alignment of Polaromonas (PnUDH) and Chromohalobacter (CsUDH) sequences with those of the three Pseudomonas species indicates a much lower 38% identity overall, though residues V75, N111, H112, Ser164, Phe166, Arg173, Met174, and Phe257 identified as being involved in substrate binding [1] are nevertheless conserved. It has been previously shown that residues corresponding to Asp33, Asp 50, Tyr135, and Lys 139 in CsUDH crystal structure [1] are involved in NAD + cofactor binding of 3-hydroxyacyl-CoA dehydrogenase [27], and these residues are strictly conserved in all Table 1 UDH enzymes; the classical Rossmann-fold motif [28] is also present in all the UDH enzymes (Fig. 2).…”

“…library.cornell.edu/usda/current/CropProdSu/CropProdSu-01-10-2014.pdf). Pectins are currently used primarily as animal feed or discarded; the use as livestock feed involves drying the pulp to preclude spoilage, with an attendant energy requirement 30-40% of the total energy input for beet processing [1,2], while disposal incurs added expense, and it is thus becoming economically and environmentally desirable to develop value-added products from these bio-resources. Structurally, pectins comprise a family of heterogeneous polysaccharides from plant primary cell walls wherein d-galacturonic acid (GalUA) occurs in abundance, and they can be grouped as homogalacturonan (HG), xylogalacturonan, rhamnogalacturonan I, and rhamnogalacturonan II [3].…”

Chemical composition, saccharification yield, and the potential of the green seaweed Ulva pertusa

“…The low degree of reductance of U. pertusa is due to its high GlcUA content, whose degree of reductance is 3.33. Recently, we found a novel gene encoding a protein that converts GlcUA to D-glucaric acid using NAD + as a coenzyme [37]. Thus, the GlcUA component in U. pertusa can be easily converted to D-glucaric acid through a one-step enzyme reaction.…”