| GenProp0736 |
proposed phosphonate catabolism pathway HpnWXZ~The enzyme phosphonatase (PhnX) catalyzes the hydrolysis of phosphonoacetaldehyde via a bicatalytic mechanism involving a specific enzyme lysine which forms a Shiff base with the aldehyde, and a magnesium-aspartate (HAD-type) nucleophile to cleave the (now-activated) phosphonate carbon-phosphorous bond. The model for PhnX (TIGR01422) effectively identifies the clade of enzymes which are associated with the PhnW enzyme that provides the substrate for the reaction. Genes mosty closely related to PhnX (modelled by TIGR03351, HpnX) share a significant degree of similarity at critical catalytic sites suggesting that it, too, acts as a phosphonatase on a beta-phosphonoaldehyde. HpnX genes are often found in the vicinity of (and uniformly in the same genomes with) a family of FAD-dependent oxidoreductases (TIGR03364, HpnW). These genes may act in an analagous fashion to PhnW by converting an aminophosphonate into an aldehyde, here by oxidative deamination. HpnW genes are members of a larger family of genes (PF01266) including enzymes with amino acid deaminating oxidase activities. This pair of genes often also is associated with a family of Zn++ dependent alcohol dehydrogenases of the PF00107 family (TIGR0####). Other genes in the vicinity of these three indicate a phosphonate-related context and are typically observed near other phosphonate catabolic pathways such as genes of the HDIG domain family (PF01966), certain GntR-type transcriptional regulators and phosphonate-related transporters. |
None - {{∅}} |
False - {{f}} |
Unconfirmed absence |
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