Electron paramagnetic resonance studies on the high-salt form of bovine spleen purple acid phosphatase.
Electron paramagnetic resonance studies on the high-salt form of bovine spleen purple acid phosphatase.
复制标题
高盐型牛脾紫色酸性磷酸酶的电子顺磁共振研究。
DOI：
10.1021/bi00155a012
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发表时间：
1992
期刊：
影响因子：
2.9
通讯作者：
Averill,BA
中科院分区：
文献类型：
--
作者：
Crowder,MW;Vincent,JB;Averill,BA
摘要：在4-30 K温度范围内，研究了还原牛脾紫色酸性磷酸酶（BSPAP）的高盐形式及其与抑制性四面体含氧阴离子、AMP和氟的复合物的EPR谱。BAPAP的高盐形式的EPR谱与先前报道的低盐形式的EPR谱相同（Averill et al.等人（1987）J. Am. Soc.109，3760-3767），表明两种形式的构象的实质性差异导致双核铁中心的电子结构的不可检测的改变。磷酸盐、AMP和砷酸盐都导致增宽的、高度各向异性的EPR光谱，反铁磁耦合常数-27的值降低，而钼酸盐和钨酸盐分别产生尖锐的轴向或轻微的菱形光谱，氟化物产生具有逆g张量的异常光谱。这些结果与两类含氧阴离子（和AMP）在双核铁中心处或附近的不同位点的结合是一致的，而氟化物以第三种模式结合。BSPAP的EPR谱，与BSPAP复合物显示在磷酸盐存在下改变的弛豫行为，与-27的幅度降低50%一致，这表明磷酸盐结合到β-内酰胺酶复合物上，产生类似于基于动力学研究提出的β-内酰胺酶抑制的三元复合物。催化核苷酸二磷酸和三磷酸、磷酸氨基酸和芳基磷酸水解的磷蛋白磷酸酶（Vincent & Averill，1990）。两个最彻底研究的例子，来自猪子宫液（子宫铁蛋白，Uf）和牛脾（BSPAP）的那些，已经通过广泛的光谱和物理技术，包括UV-可见光、共振拉曼、NMR、EPR、ENDOR、EXAFS和穆斯堡尔光谱和直接磁化率测量（总结于Antanaitis & Aisen，1983; Doi等人，1988年a; Que & True，
Revised Manuscript Received July 13, 1992 abstract: The EPR spectra of the high-salt formof reduced bovine spleen purple acid phosphatase (BSPAP,) and its complexes with inhibitory tetrahedral oxyanions, AMP, and fluorine have been examined in the 4-30 K temperature range. The EPR spectrum of the high-saltform of BAPAP, is identical to that previously reported for the low-saltform (Averill et al.(1987) J. Am. Chem. Soc. 109, 3760-3767), indicating that the substantial differences in conformation of the twoforms result in undetectable alterations in the electronic structure of the binuclear iron center. Phosphate, AMP, and arsenate all result in broadened, highly anisotropic EPR spectra with decreased values of the antiferromagnetic coupling constant,-27, while molybdate and tungstate produce a sharp axial or slightly rhombic spectrum, respectively, and fluoride produces an anomalous spectrum with an inverted g-tensor. These results are consistent with binding of the two classes of oxyanions (and AMP) to distinct sites at or near the binuclear iron center, while fluoride binds in yet a third mode. EPR spectra of the BSPAP, complex with molybdate show altered relaxation behavior in the presence of phosphate, consistent with a 50% decrease in the magnitude of-27, suggesting that phosphate binds to the molybdate complex to produce a ternary complexanalogous to that proposed for molybdate inhibition on the basis of kinetics studies.Purple acid phosphatases (PAP’s) 1 are a class of phos-phoprotein phosphatases that catalyze the hydrolysis of nucleotide di-and triphosphates, phosphoamino acids, and aryl phosphates (Vincent & Averill, 1990). The two most thoroughly studied examples, those from porcine uterine fluid (uteroferrin, Uf) and bovine spleen (BSPAP), have been examined by a wide array of spectroscopic and physical techniques, including UV-visible, resonance Raman, NMR, EPR, ENDOR, EXAFS, and Mossbauer spectroscopy and direct magnetic susceptibility measurements (summarized in Antanaitis & Aisen, 1983; Doi et al., 1988a; Que & True,