UDP‐glucose dehydrogenase from bovine liver: Primary structure and relationship to other dehydrogenases

Abstract

The primary structure of bovine liver UDP-glucose dehydrogenase (UDPGDH), a hexameric, NAD+-linked enzyme, has been determined at the protein level. The 52-kDa subunits are composed of 468 amino acid residues, with a free N-terminus and a Ser/Asn microheterogeneity at one position. The sequence shares 29.6% positional identity with GDP-mannose dehydrogenase from Pseudomonas, confirming a similarity earlier noted between active site peptides. This degree of similarity is comparable to the 31.1% identity vs. the UDPGDH from type A Streptococcus. Database searching also revealed similarities to a hypothetical sequence from Salmonella typhimurium and to "UDP-N-acetyl-mannosaminuronic acid dehydrogenase" from Escherichia coli. Pairwise identities between bovine UDPGDH and each of these sequences were all in the range of -26-34%. Multiple alignment of all 5 sequences indicates common ancestry for these 4-electron-transferring enzymes. There are 27 strictly conserved residues, including a cysteine residue at position 275, earlier identified by chemical modification as the expected catalytic residue of the second half-reaction (conversion of UDP-aldehydoglucose to UDP-glucuronic acid), and 2 lysine residues, at positions 219 and 338, one of which may be the expected catalytic residue for the first half-reaction (conversion of UDP-glucose to UDP-aldehydoglucose). A GXGXXG pattern characteristic of the coenzyme-binding fold is found at positions 11-16, close to the N-terminus as with "short-chain" alcohol dehydrogenases. Because the enzyme combines functionalities of alcohol and aldehyde dehydrogenases, it was also of interest to search specifically for other sequence similarities to either of these 2 enzymes, as well as to histidinol dehydrogenase, another 4-electron-transferring dehydrogenase, but none were found.

UGD1 , Encoding the Cryptococcus neoformans UDP-Glucose Dehydrogenase, Is Essential for Growth at 37°C and for Capsule Biosynthesis

“…2). We identified the UDP-glucose dehydrogenase gene in the C. neoformans genome (http: //www.broad.mit.edu/annotation/fungi/cryptococcus_neoformans /index.html) by looking for sequence homologies with the corresponding bovine gene (19). Moreover, two traces of cDNA sequences specific for this gene were identified at the Oklahoma Sequencing Center (http://www.genome.ou.edu/cneo.html), and these enabled us to determine the 3Ј and 5Ј extremity sequences.…”

TheCaenorhabditis elegansvulval morphogenesis genesqv-4encodes a UDP-glucose dehydrogenase that is temporally and spatially regulated

“…2B). UDP-glucose dehydrogenase catalyzes the conversion of UDP-glucose to UDP-glucuronic acid (19,22). Two molecules of NAD ϩ are converted to NADH for each molecule of UDP-glucuronic acid that is generated (23).…”

Importance of Gly-13 for the Coenzyme Binding of Human UDP-glucose Dehydrogenase

“…Because glucuronate is a component of glycosaminoglycans (GAGs), the mutation inactivation of UGDH (sugarless) abolishes GAG assembly and, consequently, abolishes GAG-dependent growth factor signaling (9 -11). The primary structure of the mammalian enzyme was obtained from the protein sequence of bovine UGDH (12). The human gene was also recently cloned and assigned to chromosome 4p15.1 (13).…”