A gene cluster responsible for alkylaldoxime metabolism coexisting with nitrile hydratase and amidase in Rhodococcus globerulus A-4.
An enzyme "alkylaldoxime dehydratase (OxdRG)" was purified and characterized from Rhodococcus globerulus A-4, in which nitrile hydratase (NHase) and amidase coexisted with the enzyme. The enzyme contains heme b as a prosthetic group, requires reducing reagents for the reaction, and is most active at a neutral pH and at around 30 degrees C, similar to the phenylacetaldoxime dehydratase from Bacillus sp. OxB-1 (OxdB). However, some differences were seen in subunit structure, substrate specificity, and effects of activators and inhibitors. The corresponding gene, oxd, encoding a 1059-base pair ORF consisting of 353 codons, was cloned, sequenced, and overexpressed in Escherichia coli. The predicted polypeptide showed 30.3% identity to OxdB. The gene is mapped just upstream of the gene cluster encoding the enzymes involved in the metabolism of aliphatic nitriles, i.e., NHase and amidase, and their regulatory and activator proteins. We report here the existence of an aldoxime dehydratase genetically linked with NHase and amidase, and responsible for the metabolism of alkylaldoxime in R. globerulus.
Xie
Sheng-Xue
SX
Biotechnology Research Center, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Kosugi, Toyama 939-0398, Japan.
Kato
Yasuo
Y
Komeda
Hidenobu
H
Yoshida
Satoshi
S
Asano
Yasuhisa
Y
D024506:5' Flanking Region / Q000235:genetics; D000581:Amidohydrolases / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004789:Enzyme Activation / Q000187:drug effects; D006420:Hemeproteins / Q000737:chemistry; D006836:Hydro-Lyases / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D010091:Oximes / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D019163:Reducing Agents / Q000737:chemistry; D012240:Rhodococcus / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D013053:Spectrophotometry; D013379:Substrate Specificity; D013696:Temperature
D006420:Hemeproteins; D010091:Oximes; D011994:Recombinant Proteins; D019163:Reducing Agents; D000581:Amidohydrolases; C019665:amidase; D006836:Hydro-Lyases; C412124:aldoxime dehydratase; C048831:nitrile hydratase; C023728:acetaldehyde oxime