Iron(II)- and 2-(oxo)-glutarate-dependent oxygenases catalyze diverse oxidative transformations that are often initiated by abstraction of hydrogen from carbon by iron(IV)-oxo (ferryl) complexes. Control of the relative orientation of the substrate C–H and ferryl Fe–O bonds, primarily by direction of the oxo group into one of two cis-related coordination sites (termed inline and offline), may be generally important for control of the reaction outcome. Neither the ferryl complexes nor their fleeting precursors have been crystallographically characterized, hindering direct experimental validation of the offline hypothesis and elucidation of the means by which the protein might dictate an alternative oxo position. Comparison of high-resolution X-ray crystal structures of the substrate complex, an Fe(II)-peroxysuccinate ferryl precursor, and a vanadium(IV)-oxo mimic of the ferryl intermediate in the l-arginine 3-hydroxylase, VioC, reveals coordinated motions of active site residues that appear to control the intermediate geometries to determine reaction outcome.

中文翻译：

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可视化铁（II）-和2-（Oxo）-戊二酸依赖性羟化酶中的反应周期

依赖于铁（II）-和2-（氧代）-谷氨酸的加氧酶催化各种氧化转化，这些氧化转化通常是由铁（IV）-氧代（轮式）配合物从碳中夺取氢而引发的。控制底物CH和H与Fe-O键的相对取向，主要是通过将羰基变成两个顺式之一来控制相关的协调位点（称为在线和离线）通常对于控制反应结果可能很重要。Ferryl配合物或其短暂的前体均未在晶体学上进行表征，这阻碍了离线假说的直接实验验证，也阻碍了蛋白质可能决定另一种羰基位置的手段的阐明。底物复合物，Fe（II）-过氧琥珀酸酯亚铁的前体和1-精氨酸3-羟化酶VioC中亚铁中间体的钒（IV）-氧代模拟物的高分辨率X射线晶体结构比较显示似乎控制中间几何形状的活性位点残基的协调运动决定了反应的结果。