Characteristics of short‐chain alcohol dehydrogenases and related enzymes

Abstract

Different short-chain dehydrogenases are distantly related, constituting a protein family now known from at least 20 separate enzymes characterized, but with extensive differences, especially in the C-terminal third of their sequences. Many of the first known members were prokaryotic, but recent additions include mammalian enzymes from placenta, liver and other tissues, including 15-hydroxyprostaglandin, 17P-hydroxysteroid and 11 P-hydroxysteroid dehydrogenases. In addition, species variants, isozyme-like multiplicities and mutants have been reported for several of the structures. Alignments of the different enzymes reveal large homologous parts, with clustered similarities indicating regions of special functional/structural importance. Several of these derive from relationships within a common type of coenzyme-binding domain, but central-chain patterns of similarity go beyond this domain. Total residue identities between enzyme pairs are typically around 25%, but single forms deviate more or less (14-58%). Only six of the 250-odd residues are strictly conserved and seven more are conserved in all but single cases. Over one third of the conserved residues are glycine, showing the importance of conformational and spatial restrictions. Secondary structure predictions, residue distributions and hydrophilicity profiles outline a common, N-terminal coenzyme-binding domain similar to that of other dehydrogenases, and a C-terminal domain with unique segments and presumably individual functions in each case. Strictly conserved residues of possible functional interest are limited, essentially only three polar residues, Asp64, Tyr152 and Lysl56 (in the numbering of Drosophilu alcohol dehydrogenase), but no histidine or cysteine residue like in the completely different, classical medium-chain alcohol dehydrogenase family. Asp64 is in the suggested coenzyme-binding domain, whereas Tyrl52 and Lys156 are close to the center of the protein chain, at a putative inter-domain, active-site segment. Consequently, the overall comparisons suggest the possibility of related mechanisms and domain properties for different members of the short-chain family.Several highly different types of alcohol dehydrogenase and related enzymes are known [l -41. The short-chain dehydrogenase family (subunits with about 250 residues) was initially discerned from insect alcohol dehydrogenase and bacterial ribitol dehydrogenase [I, 5-71. Knowledge about this family has been rapidly growing and it now also includes prokaryotic glucose dehydrogenase, several hydroxysteroid dehydrogenases, and additional forms [7 -121. The recent finding that a mammalian 15-hydroxyprostaglandin dehydrogenase and other mammalian enzymes belong to this group [12-161, gives the family added interest also in eukaryotic metabolism. Little is known about the functional mechanisms for these short-chain enzymes, and we now show common properties and further members that establish both similarities

Polyol metabolism of Rhodobacter sphaeroides: biochemical characterization of a short-chain sorbitol dehydrogenase

“…Only the SDH of B. mbtilis (Ng e t al., 1992) (Sarthy e t al., 1994) have been included in the same enzyme family and share 36 and 42 % homology with the sequences of the mammalian SDHs, respectively. However, other microbial polyol dehydrogenases have been classified on the basis of sequence data as members of the short-chain alcohol dehydrogenase family which comprises a group of relatively small enzymes exhibiting no metal requirements (Persson et al, 1991). Enzymes of this family are RDH from Enterobacter aerogenes (Dothie e t al., 1985), arabinitol dehydrogenase from Candida albicans (Wong et al, 1993) and ~-glucitol-6-phosphate dehydrogenase from Klebsiella pnetlmoniae (EMBL accession no.…”

Drosophila lebanonensis ADH: analysis of recombinant wild‐type enzyme and site‐directed mutants

“…Our results clearly show Position 56 is threonine in all Drosophila ADHs, except D. lebanonensis (As#) and D. mayaguana (Iles6). This position is not only non-conserved among shortchain dehydrogenases, but also enclosed in a hyper-variable region, which is difficult to align [4]. However, this threonine, which lies in the third B-sheet of the NAD' binding domain, is conserved among all animal mediumchain alcohol dehydrogenases (position 238) [2].…”

“…However, no tertiary structure is yet known for Drosophila ADH and therefore the structure/function relationships must be approached through different strategies. Putative critical residues for enzyme architecture and catalytic properties, highlighted as conserved positions among all short-chain dehydrogenases and all known Drosophila ADHs [2,4,5], have been analyzed by either chemical modification [6] or site-directed mu-*Corresponding author. Fax: (34) (3) 411 09-69.…”

In silico analysis of heme oxygenase structural homologues identifies group‐specific conservations

“…This residue is found in the turn between α‐1 and α‐2 30. Conserved glycines are often found in turns in enzyme structures or at positions where a side chain would lead to steric conflicts in many enzyme families 31, 32, 33, 34. Phe47{173} is 71% conserved overall and is found in RNR1As, most thiaminases, and HOs except plant species.…”