N-Heterocyclic compounds are widely spread in the biosphere, being constituents of alkaloids, cofactors, allelochemicals, and artificial substances. However, the fate of such compounds including a catabolism of hydroxylated pyridines is not yet fully understood. Arthrobacter sp. IN13 is capable of using 4-hydroxypyridine as a sole source of carbon and energy. Three substrate-inducible proteins were detected by comparing protein expression profiles, and peptide mass fingerprinting was performed using MS/MS. After partial sequencing of the genome, we were able to locate genes encoding 4-hydroxypyridine-inducible proteins and identify the kpi gene cluster consisting of 16 open reading frames. The recombinant expression of genes from this locus in Escherichia coli and Rhodococcus erytropolis SQ1 allowed an elucidation of the biochemical functions of the proteins. We report that in Arthrobacter sp. IN13, the initial hydroxylation of 4-hydroxypyridine is catalyzed by a flavin-dependent monooxygenase (KpiA). A product of the monooxygenase reaction is identified as 3,4-dihydroxypyridine, and a subsequent oxidative opening of the ring is performed by a hypothetical amidohydrolase (KpiC). The 3-(N-formyl)-formiminopyruvate formed in this reaction is further converted by KpiB hydrolase to 3-formylpyruvate. Thus, the degradation of 4-hydroxypyridine in Arthrobacter sp. IN13 was analyzed at genetic and biochemical levels, elucidating this catabolic pathway.

中文翻译：

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关节杆菌中4-羟基吡啶分解代谢的生化和遗传分析。应变IN13。

N-杂环化合物在生物圈中广泛传播，是生物碱，辅因子，化感物质和人造物质的组成部分。然而，包括羟基化吡啶的分解代谢在内的这类化合物的命运尚未完全被理解。节藻。IN13能够使用4-羟基吡啶作为唯一的碳和能量来源。通过比较蛋白质表达谱检测了三种底物诱导蛋白，并使用MS / MS进行了肽质量指纹图谱。基因组的部分测序后，我们能够找到编码4-羟基吡啶可诱导蛋白的基因，并鉴定由16个开放阅读框组成的kpi基因簇。该基因在大肠杆菌 中的重组表达和红球菌erytropolis SQ1允许的蛋白质的生化功能澄清。我们在节杆菌中报道。在IN13中，黄素依赖性单加氧酶（KpiA）催化4-羟基吡啶的初始羟基化。单加氧酶反应的产物被鉴定为3，4-二羟基吡啶，并且随后的环的氧化打开由假设的酰胺水解酶（KpiC）进行。在该反应中形成的3-（N-甲酰基）-甲亚氨基丙酮酸酯被KpiB水解酶进一步转化为3-甲酰基丙酮酸酯。因此，节杆菌属中4-羟基吡啶的降解。在遗传和生化水平上分析了IN13，阐明了这种分解代谢途径。