Namanja Andrew T, Peng Tao, Zintsmaster John S, Elson Andrew C, Shakour Maria G, Peng Jeffrey W
Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556, USA.
Structure. 2007 Mar;15(3):313-27. doi: 10.1016/j.str.2007.01.014.
Pin1 is a peptidyl-prolyl isomerase consisting of a WW domain and a catalytic isomerase (PPIase) domain connected by a flexible linker. Pin1 recognizes phospho-Ser/Thr-Pro motifs in cell-signaling proteins, and is both a cancer and an Alzheimer's disease target. Here, we provide novel insight into the functional motions underlying Pin1 substrate interaction using nuclear magnetic resonance deuterium ((2)D) and carbon ((13)C) spin relaxation. Specifically, we compare Pin1 side-chain motions in the presence and absence of a known phosphopeptide substrate derived from the mitotic phosphatase Cdc25. Substrate interaction alters Pin1 side-chain motions on both the microsecond-millisecond (mus-ms) and picosecond-nanosecond (ps-ns) timescales. Alterations include loss of ps-ns flexibility along an internal conduit of hydrophobic residues connecting the catalytic site with the interdomain interface. These residues are conserved among Pin1 homologs; hence, their dynamics are likely important for the Pin1 mechanism.
Pin1是一种肽基脯氨酰异构酶，由一个WW结构域和一个催化异构酶（PPIase）结构域组成，二者通过一个柔性接头相连。Pin1识别细胞信号蛋白中的磷酸化丝氨酸/苏氨酸-脯氨酸基序，既是癌症的靶点，也是阿尔茨海默病的靶点。在此，我们利用核磁共振氘（2D）和碳（13C）自旋弛豫，对Pin1底物相互作用背后的功能运动提供了新的见解。具体而言，我们比较了在存在和不存在源自有丝分裂磷酸酶Cdc25的已知磷酸肽底物的情况下Pin1侧链的运动。底物相互作用在微秒-毫秒（μs-ms）和皮秒-纳秒（ps-ns）时间尺度上改变了Pin1侧链的运动。变化包括沿着连接催化位点与结构域间界面的疏水残基内部通道的ps-ns灵活性丧失。这些残基在Pin1同源物中是保守的；因此，它们的动力学可能对Pin1机制很重要。
