Common structural changes accompany the functional inactivation of HPr by seryl phosphorylation or by serine to aspartate substitution.
Common structural changes accompany the functional inactivation of HPr by seryl phosphorylation or by serine to aspartate substitution.
复制标题
常见的结构变化伴随着丝氨酰磷酸化或丝氨酸至天冬氨酸取代引起的 HPr 功能失活。
DOI：
10.1021/bi00452a005
复制
发表时间：
1989
期刊：
影响因子：
2.9
通讯作者：
Klevit,RE
中科院分区：
文献类型：
--
作者：
Wittekind,M;Reizer,J;Deutscher,J;Saier,MH;Klevit,RE
1989年11月6日收到的修订手稿摘要：尽管已知许多蛋白质是通过可逆磷酸化来调节的，但对丝氨基、苏氨基或酪氨酸残基的共价修饰改变靶系统活性的机制知之甚少。为了解决这个问题，对细菌磷酸转移酶系统的蛋白质组分枯草芽孢杆菌HPR的修饰形式进行了研究。Ser46位的磷酸化或该位置的Ser到Asp的替换可使HPR失活[Reizer，J.，Sutrina，S.L.，Saier，M.H.，Stewart，G.C.，Peterkofsky，A.，&Reddy，P.()EMBO J.8,2111-2120]，这两个修饰蛋白的二维谱显示出几乎相同的质子化学位移，与未磷酸化的野生型蛋白和具有功能活性的HPR突变体的谱中观察到的质子化学位移显著不同。结果表明，丝氨酸对天冬氨酸突变引起的hpr的功能失活伴随着与hpr在Ser46位发生磷酸化时相同的结构变化。蛋白质的可逆磷酸化是在真核生物和原核生物中广泛使用的一种调节细胞活性的机制(Krebs，1985；Cozzone，1988)。然而，只有一种蛋白质的非磷酸化和磷酸化形式都有结构信息；X射线结晶学技术表明，糖原磷酸化酶在Ser14的磷酸化后经历了构象变化(Sprang等人，1988年)。这些变化影响亚单位界面，并影响酶对变构调节剂的反应。显然，对结构的研究
Revised Manuscript Received November 6, 1989 abstract: Although manyproteins are known to be regulated via reversible phosphorylation, little is known about the mechanism by which the covalent modification of seryl, threonyl, or tyrosyl residues alters the activities of the target systems. To address this question, modified versions of Bacillus subtilus HPr, a protein component of the bacterial phosphotransferase system, havebeen studied by'Hnmr spectroscopy. Phosphorylation at Ser46 or a Ser to Asp substitution at this position inactivates HPr [Reizer, J., Sutrina, S. L., Saier, M. H., Stewart, G. C., Peterkofsky, A., & Reddy, P.(1989) EMBO J. 8, 2111-2120], Two-dimensional spectra of these two modified proteins display nearly identical proton chemical shifts that differ significantly from those observed in the spectra of the unphosphorylated, wild-type protein and of functionally active HPr mutants. The results demonstrate that the functional inactivation of HPr brought about by the serine to aspartate mutation is accompanied by the same structural changes that occur when HPr is phosphorylated at Ser46.^ IReversible phosphorylation of proteins, catalyzed by protein kinases and phosphatases, is a widely used mechanism for regulation of cellularactivities in both eukaryotesand pro-karyotes (Krebs, 1985; Cozzone, 1988). There is, however, only one protein for which there is structural information for both its unphosphorylated and phosphorylated forms; glycogen phosphorylase has been shown by X-ray crystallographic techniques to undergo a conformational change upon phos-phorylation of Ser14 (Sprang et al., 1988). These changes affect the subunit interface and influence theenzyme’s re-sponse to allosteric regulators. Clearly, structural studies on