Ajinomoto-Genetika Research Institute, Moscow, Russia.
FEMS Microbiol Lett. 2012 Jun;331(2):97-104. doi: 10.1111/j.1574-6968.2012.02558.x. Epub 2012 Apr 13.
L-isoleucine-4-hydroxylase (IDO) is a recently discovered member of the Pfam family PF10014 (the former DUF 2257 family) of uncharacterized conserved bacterial proteins. To uncover the range of biochemical activities carried out by PF10014 members, eight in silico-selected IDO homologues belonging to the PF10014 were cloned and expressed in Escherichia coli. L-methionine, L-leucine, L-isoleucine and L-threonine were found to be catalysed by the investigated enzymes, producing L-methionine sulfoxide, 4-hydroxyleucine, 4-hydroxyisoleucine and 4-hydroxythreonine, respectively. An investigation of enzyme kinetics suggested the existence of a novel subfamily of bacterial dioxygenases within the PF10014 family for which free L-amino acids could be accepted as in vivo substrates. A hypothesis regarding the physiological significance of hydroxylated l-amino acids is also discussed.
L-异亮氨酸-4-加双氧酶（IDO）是 Pfam 家族 PF10014（以前的 DUF 2257 家族）中一个最近发现的未明确功能的细菌蛋白保守家族成员。为了揭示 PF10014 成员所执行的生化活性范围，我们从计算机中选择了 8 个 IDO 同源物并将其在大肠杆菌中进行克隆和表达。研究发现，所研究的酶能够催化 L-蛋氨酸、L-亮氨酸、L-异亮氨酸和 L-苏氨酸的反应，分别生成 L-蛋氨酸亚砜、4-羟化亮氨酸、4-羟基异亮氨酸和 4-羟基苏氨酸。对酶动力学的研究表明，PF10014 家族中存在一个新的细菌双氧酶亚家族，其可接受游离的 L-氨基酸作为体内底物。我们还讨论了关于羟化 L-氨基酸的生理意义的假设。
