A periplasmic quinoprotein alcohol dehydrogenase that only occurs in methylotrophic bacteria. It uses the novel specific cytochrome cL as acceptor. Acts on a wide range of primary alcohols, including ethanol, duodecanol, chloroethanol, cinnamyl alcohol, and also formaldehyde. Activity is stimulated by ammonia or methylamine. It is usually assayed with phenazine methosulfate. Like all other quinoprotein alcohol dehydrogenases it has an 8-bladed 'propeller' structure, a calcium ion bound to the PQQ in the active site and an unusual disulfide ring structure in close proximity to the PQQ. It differs from EC 1.1.2.8, alcohol dehydrogenase (cytochrome c), in having a high affinity for methanol and in having a second essential small subunit (no known function).
History
EC 1.1.2.7 created 1972 as EC 1.1.99.8, modified 1982, part transferred 2010 to EC 1.1.2.7
Afolabi PR, Mohammed F, Amaratunga K, Majekodunmi O, Dales SL, Gill R, Thompson D, Cooper JB, Wood SP, Goodwin PM, Anthony C
Title
Site-directed mutagenesis and X-ray crystallography of the PQQ-containing quinoprotein methanol dehydrogenase and its electron acceptor, cytochrome c(L).
A periplasmic PQQ-containing quinoprotein. Occurs in Pseudomonas and Rhodopseudomonas. The enzyme from Pseudomonas aeruginosa uses a specific inducible cytochrome c550 as electron acceptor. Acts on a wide range of primary and secondary alcohols, but not methanol. It has a homodimeric structure [contrasting with the heterotetrameric structure of EC 1.1.2.7, methanol dehydrogenase (cytochrome c)]. It is routinely assayed with phenazine methosulfate as electron acceptor. Activity is stimulated by ammonia or amines. Like all other quinoprotein alcohol dehydrogenases it has an 8-bladed 'propeller' structure, a calcium ion bound to the PQQ in the active site and an unusual disulfide ring structure in close proximity to the PQQ.
History
EC 1.1.2.8 created 1972 as EC 1.1.99.8, modified 1982, part transferred 2010 to EC 1.1.2.8
Cytochrome c550 is an essential component of the quinoprotein ethanol oxidation system in Pseudomonas aeruginosa: cloning and sequencing of the genes encoding cytochrome c550 and an adjacent acetaldehyde dehydrogenase.
Characterisation of the PQQ cofactor radical in quinoprotein ethanol dehydrogenase of Pseudomonas aeruginosa by electron paramagnetic resonance spectroscopy.
Quinoprotein ethanol dehydrogenase from Pseudomonas aeruginosa: the unusual disulfide ring formed by adjacent cysteine residues is essential for efficient electron transfer to cytochrome c550.
