Dehydrogenases domains

A rather common feature of subunit contacts is ft sheet hydrogenbonding between strands in opposite subunits. Theoretically the relationship could be a pure translation or a 2-fold screw axis with a one-residue translation (for a pair of parallel strands), but all the known cases of intersubunit /3 sheet bonding turn out to be between equivalent strands related by a local 2-fold axis. For hydrogen-bond formation, the 2-fold must be perpendicular to the /3 sheet, requiring the two equivalent strands to be antiparallel. Those may be the only two /3 strands (as in insulin, Fig. 63), or they may be part of antiparallel P sheets (as in prealbumin, Fig. 62), or the rest of the sheets may be parallel (as in alcohol dehydrogenase domain 1). 

Classic doubly wound /3 sheets Lactate dehydrogenase domain 1 Alcohol dehydrogenase domain 2 Aspartate transcarbamylase catalytic domain 2 Phosphoglycerate kinase domain 1 Tyrosyl-tRNA synthetase domain 1( )... 

Doubly wound variations Glyceraldehyde-phosphate dehydrogenase domain 1 Phosphorylase domain 1, central three layers Flavodoxin... 

C. Multiple, partial, and other /3 barrels Acid proteases domains 1 and 2 Alcohol dehydrogenase domain 1 Pancreatic ribonuclease... 

Glyceraldehyde-phosphate dehydrogenase domain 2 Bacteriochlorophyll protein p-Hydroxybenzoate hydroxylase domain 2 Influenza virus hemagglutinin HA2 L7/L12 ribosomal protein... 

E. Miscellaneous antiparallel /3 Gene 5 protein, E. coli Lactate dehydrogenase domain 2 Tomato bushy stunt virus protein domain 1 IV. Small disulfide-rich or metal-rich domains... 

Fig. 92. Lactate dehydrogenase domain 1 as an example of a classic doubly wound parallel P sheet, (a) a-Carbon stereo, viewed from one edge of the sheet (b) backbone schematic, viewed as in a (c) backbone schematic, viewed from one face of the sheet.

Krawczyk S, Raasch K, Schultz C, Hoffelder M, Eggeling L, Bott M. (2010). The FHA domain of OdhI interacts with the carboxyterminal 2-oxoglutarate dehydrogenase domain of OdhA in Corynebacterium glutamicum. FEBS Lett, 584, 1463—1468. 

Figure 4. "Richardson diagrams" [29] of five proteins illustrating four classes of tertiary-fold motifs typically found in globular proteins, (a) AU-a hemoglobin, P subunit, (b) AU- Immunoglobulin variable domain, (c) o/p tnose phosphate isomerase. (d) ot/p alcohol dehydrogenase, domain 2. (e) a+ Stai ylococcal nuclease.

Cellobiose dehydrogenase (CDH) is another enzyme that has been explored for its potential to undergo DET. CDH consists of an FAD-dependent dehydrogenase domain, which is responsible for the oxidation of substrates, and an additional cytochrome heme-containing domain. Following the 2e oxidation of a substrate at the FAD-dehydrogenase domain, an electron mediator (such as hydroquinone) can be employed to transfer electrons between the FAD-dehydrogenase domain and an electrode. In a similar fashion to PQQ-AldDH and... 

Barthe et al. (2009) solved the structure of the phosphorylated and unphosphorylated forms of Odhl. The phosphothreonine residue in OdW interacts with its own FHA domain, and as a result, phosphorylated Odhl cannot interact with OdhA to inhibit ODHC activity. In contrast, the FHA domain in unphosphorylated Odhl can freely interact with OdhA, and thereby inhibit ODHC activity. Biochemical analyses revealed that the FHA domain of unphosphorylated Odhl interacts with the C-terminal dehydrogenase domain of OdhA (Krawczyk et al. 2010). 

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