X-ray absorption spectroscopic investigation of the resting ferrous and cosubstrate-bound active sites of phenylalanine hydroxylase.
X-ray absorption spectroscopic investigation of the resting ferrous and cosubstrate-bound active sites of phenylalanine hydroxylase.
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X 射线吸收光谱研究苯丙氨酸羟化酶的静止亚铁和共底物结合活性位点。
DOI：
10.1021/bi0121510
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发表时间：
2002
期刊：
影响因子：
2.9
通讯作者：
Hodgson,KeithO
中科院分区：
文献类型：
--
作者：
Wasinger,ErikC;Mitić,Natasa;Hedman,Britt;Caradonna,John;Solomon,EdwardI;Hodgson,KeithO
先前对亚铁野生型苯丙氨酸羟基酶的研究表明，该酶的活性部位为六配位扭曲的八面体。底物和辅因子与酶({Fe2+}PAHR[L-Phe，5-去氮-6-MPH4])结合后，活性中心转变为五坐标正方形金字塔结构，其中缺失的配体的身份尚未确定。Fe K边的X射线吸收光谱(XAS)进一步支持了这一配位数的变化，因为两种共底物都与酶结合，并确定这是由于失去了一个水配体。
Previous studies of ferrous wild-type phenylalanine hydroxylase, {Fe2+}PAHT[], have shown the active site to be a six-coordinate distorted octahedral site. After the substrate and cofactor bind to the enzyme ({Fe2+}PAHR[l-Phe,5-deaza-6-MPH4]), the active site converts to a five-coordinate square pyramidal structure in which the identity of the missing ligand had not been previously determined. X-ray absorption spectroscopy (XAS) at the Fe K-edge further supports this coordination number change with the binding of both cosubstrates to the enzyme, and determines this to be due to the loss of a water ligand.