The crystal structure of a phosphorylase kinase peptide substrate complex: kinase substrate recognition
The crystal structure of a phosphorylase kinase peptide substrate complex: kinase substrate recognition
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DOI：
10.1093/emboj/16.22.6646
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发表时间：
1997-11-17
期刊：
影响因子：
11.4
通讯作者：
Johnson, LN
中科院分区：
文献类型：
--
作者：
Lowe, ED;Noble, MEM;Johnson, LN
磷酸化酶激酶γ亚基截短型的结构（PHK γ（t））与不可水解的ATP类似物形成三元复合物（腺苷酰亚胺二磷酸，AMPPNP）和在序列上与天然底物和最佳肽底物两者相关的七肽底物。磷酸转移反应的动力学表征证实肽是良好的底物，并且该结构允许鉴定负责其高亲和力的关键特征。出乎意料的是，底物肽与激酶活化片段形成短的反平行β折叠，该区域在其它激酶中在酶活性调节中起重要作用，底物肽的主链与ATP的γ-磷酸的固定距离的锚定解释了PHK对丝氨酸/苏氨酸的选择性超过酪氨酸作为底物，PHK的催化核心作为二聚体存在于三元复合物的晶体中，并且考虑了这种现象与其体内识别二聚体糖原磷酸化酶B的相关性。
The structure of a truncated form of the gamma-subunit of phosphorylase kinase (PHK gamma(t)) has been solved in a ternary complex with a non-hydrolysable ATP analogue (adenylyl imidodiphosphate, AMPPNP) and a heptapeptide substrate related in sequence to both the natural substrate and to the optimal peptide substrate, Kinetic characterization of the phosphotransfer reaction confirms the peptide to be a good substrate, and the structure allows identification of key features responsible for its high affinity, Unexpectedly, the substrate peptide forms a short anti-parallel beta-sheet with the kinase activation segment, the region which in other kinases plays an important role in regulation of enzyme activity, This anchoring of the main chain of the substrate peptide at a fixed distance from the gamma-phosphate of ATP explains the selectivity of PHK for serine/threonine over tyrosine as a substrate, The catalytic core of PHK exists as a dimer in crystals of the ternary complex, and the relevance of this phenomenon to its in vivo recognition of dimeric glycogen phosphorylase b is considered.