Deletion of the pcaHG genes, encoding protocatechuate 3,4-dioxygenase in Rhodococcus jostii RHA1, gives a gene deletion strain still able to grow on protocatechuic acid as the sole carbon source, indicating a second degradation pathway for protocatechuic acid. Metabolite analysis of wild-type R. jostii RHA1 grown on medium containing vanillin or protocatechuic acid indicated the formation of hydroxyquinol (benzene-1,2,4-triol) as a downstream product. Gene cluster ro01857-ro01860 in Rhodococcus jostii RHA1 contains genes encoding hydroxyquinol 1,2-dioxygenase and maleylacetate reductase for degradation of hydroxyquinol but also putative mono-oxygenase (ro01860) and putative decarboxylase (ro01859) genes, and a similar gene cluster is found in the genome of lignin-degrading Agrobacterium species. Recombinant R. jostii mono-oxygenase and decarboxylase enzymes in combination were found to convert protocatechuic acid to hydroxyquinol. Hence, an alternative pathway for degradation of protocatechuic acid via oxidative decarboxylation to hydroxyquinol is proposed.

中文翻译：

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香球菌RHA1和农杆菌属物种中的羟基喹啉降解途径是原儿茶酸和木质素片段降解的另一种途径。

所述的缺失pcaHG基因，编码原儿茶酸在3,4-双加氧酶红球菌jostii RHA1，给出了一个基因缺失菌株仍然能够在原儿茶酸成长为唯一碳源，表明原儿茶酸的第二降解途径。在含有香兰素或原儿茶酸的培养基上生长的野生型约氏假丝酵母RHA1的代谢物分析表明，形成了下游产物羟喹醇（苯-1,2,4-三醇）。红球菌中的基因簇ro01857- ro01860RHA1包含编码用于降解羟基喹诺酚的羟基喹啉1,2-二加氧酶和马来酰乙酸还原酶的基因，还包含推定的单加氧酶（ro01860）和推定的脱羧酶（ro01859）基因，并且在木质素降解农杆菌物种的基因组中发现了类似的基因簇。。已发现重组重组约瑟夫氏单加氧酶和脱羧酶可将原儿茶酸转化为羟基喹啉。因此，提出了通过氧化脱羧为羟基喹啉降解原儿茶酸的替代途径。