Structural and functional consequences of cardiac troponin C L57Q and I61Q Ca(2+)-desensitizing variants.
Structural and functional consequences of cardiac troponin C L57Q and I61Q Ca(2+)-desensitizing variants.
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心肌肌钙蛋白 C L57Q 和 I61Q Ca(2 ) 脱敏变体的结构和功能后果。
DOI：
10.1016/j.abb.2013.02.006
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发表时间：
2013
影响因子：
3.9
通讯作者：
Regnier,Michael
中科院分区：
文献类型：
--
作者：
Wang,Dan;McCully,MichelleE;Luo,Zhaoxiong;McMichael,Jonathan;Tu,An-Yue;Daggett,Valerie;Regnier,Michael
两种cTnC变体，L57 Q和I61 Q，均位于cTnC N结构域内的螺旋C上，最初在骨骼肌系统中被报道[Tikunova，Davis，J.Biol.Chem.279（2004）35341-35352]，作为类似的L58 Q和I62 Q sTnC，并显示出降低的Ca 2+结合亲和力。在这里，我们提供了这两种cTnC变体的结构-功能关系的详细表征，以确定它们在心脏系统中的行为是否不同，并作为确定与DCM相关的其他cTnC突变的相似性和差异的框架。我们使用了一种综合的方法来研究这些cTnC变体的结构和功能，包括溶液和计算机模拟，以了解L57 Q和I61 Q突变如何影响位点II的Ca 2+结合，随后对与cTnI相互作用的影响，以及与这些变化相关的结构变化。稳态和停流荧光光谱证实，含有L57 Q或I61 Q变体的重组cTnC和cTnC复合物的Ca 2+亲和力降低。L57 Q变体介于WT和I61 Q cTnC之间，在不存在Ca 2+的情况下也未显著改变cTnC-cTnI相互作用，但在存在Ca 2+的情况下确实降低了相互作用。相反，I61 Q在不存在和存在Ca 2+的情况下均降低cTnC-cTnI相互作用。在缺乏Ca 2+的情况下的这种差异表明，与L57 Q突变相比，I61 Q突变可能发生更大的cNTnC结构变化。分子动力学模拟结果表明，I61 Q诱导的Ca 2+结合减少可能是由于残基61与G70在Ca 2+结合环上形成新的氢键时，通过中断分子内相互作用使Ca 2+结合位点不稳定所致。实验观察到的L57 Q或I61 Q引起的cTnC-cTnI相互作用中断是由于cNTnC中螺旋B和C之间的关键疏水相互作用中断。这项研究提供了cTnC螺旋中的单个突变如何降低Ca 2+结合亲和力和cTnC-cTnI相互作用的分子基础，这可能为更好地理解心肌病和未来的基因治疗提供有用的见解。
Two cTnC variants, L57Q and I61Q, both of which are located on helix C within the N domain of cTnC, were originally reported in the skeletal muscle system [Tikunova, Davis, J. Biol. Chem. 279 (2004) 35341–35352], as the analogous L58Q and I62Q sTnC, and demonstrated a decreased Ca2+binding affinity. Here, we provide detailed characterization of structure–function relationships for these two cTnC variants, to determine if they behave differently in the cardiac system and as a framework for determining similarities and differences with other cTnC mutations that have been associated with DCM. We have used an integrative approach to study the structure and function of these cTnC variants both in solution and in silico, to understand how the L57Q and I61Q mutations influence Ca2+binding at site II, the subsequent effects on the interaction with cTnI, and the structural changes which are associated with these changes. Steady-state and stopped flow fluorescence spectroscopy confirmed that a decrease in Ca2+affinity for recombinant cTnC and cTn complexes containing the L57Q or I61Q variants. The L57Q variant was intermediate between WT and I61Q cTnC and also did not significantly alter cTnC–cTnI interaction in the absence of Ca2+, but did decrease the interaction in the presence of Ca2+. In contrast, I61Q decreased the cTnC–cTnI interaction in both the absence and presence of Ca2+. This difference in the absence of Ca2+suggests a greater structural change in cNTnC may occur with the I61Q mutation than the L57Q mutation. MD simulations revealed that the decreased Ca2+binding induced by I61Q may result from destabilization of the Ca2+binding site through interruption of intra-molecular interactions when residue 61 forms new hydrogen bonds with G70 on the Ca2+binding loop. The experimentally observed interruption of the cTnC–cTnI interaction caused by L57Q or I61Q is due to the disruption of key hydrophobic interactions between helices B and C in cNTnC. This study provides a molecular basis of how single mutations in the C helix of cTnC can reduce Ca2+binding affinity and cTnC–cTnI interaction, which may provide useful insights for a better understanding of cardiomyopathies and future gene-based therapies.
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心肌肌钙蛋白 C L48Q Ca(2 ) 敏化突变的结构和功能后果。
影响因子：
2.9
作者：
Wang,Dan;Robertson,IanM;Li,MonicaX;McCully,MichelleE;Crane,MelissaL;Luo,Zhaoxiong;Tu,An-Yue;Daggett,Valerie;Sykes,BrianD;Regnier,Michael
通讯作者：
Regnier,Michael
影响因子：
2.9
作者：
M. E. McCully;David A. C. Beck;V. Daggett
通讯作者：
M. E. McCully;David A. C. Beck;V. Daggett
在日益复杂的生化系统中，钙敏化突变对钙结合以及与肌钙蛋白 C 交换的影响。
影响因子：
2.9
作者：
Tikunova,SvetlanaB;Liu,Bin;Swindle,Nicholas;Little,SeanC;Gomes,AldrinV;Swartz,DarlR;Davis,JonathanP
通讯作者：
Davis,JonathanP
Kojima，S.，等人：“组织转谷氨酰胺酶对中期因子的二聚化及其功能意义”J Biol Chem。
DOI：
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发表时间：
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期刊：
影响因子：
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作者：
通讯作者：
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影响因子：
4
作者：
Patton, C;Thompson, S;Epel, D
通讯作者：
Epel, D