STRUCUTRAL STUDIES OF THE KAR3-VIK1, KAR3-CIK1 HETERODIMER MOTOR PROTEINS

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 本研究主要针对运动蛋白-14类马达中的Kar3的分子机制进行研究。Kinesin-14马达的成员是负端定向的、非进行性的Kinesin，使用PowerStroke机制进行操作。Kar3代表了一个独特的机会来研究非进行性多聚体运动蛋白中常见的功能不对称，包括同源二聚体，如NCD，因为Kar3与Vik1或Cik1一起作为异源二聚体发挥作用。Vik1和Cik1不是分子马达，但我们最近发现，Vik1包含一个球状结构域，它与Kinesin运动域具有相同的折叠。这个结构域与微管的结合比Kar3更紧密，但不能水解ATP。这就要求在马达和非马达结构域之间存在分子间的通信，以产生运动。根据序列相似性，预测Cik1含有一个运动同源结构域。因此，凯瑟琳的研究应该为非进行性分子马达中常见的功能不对称提供有价值的见解。核磁共振将被用来合成高容量的链球菌色谱柱，这将有助于Kar3-Vik1和Kar3-Cik1杂二聚体的纯化。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This research focuses on the molecular mechanism for Kar3 which belongs to the Kinesin-14 class of motors. Members of the Kinesin-14 motors are minus-end directed, non processive kinesins that operate with a powerstroke mechanism. Kar3 represents a unique opportunity to study the common functional asymmetry in non processive multimeric kinesins, including homodimeric examples such as Ncd, as Kar3 functions as a heterodimer with either Vik1 or Cik1. Vik1 and Cik1 are not molecular motors, yet we have recently shown that Vik1 contains a globular domain that exhibits the same fold as the kinesin motor domain. This domain binds more tightly to microtubules than Kar3, but does not hydrolyze ATP. This demands the existence of intermolecular communication between the motor and non motor domains in order to generate movement. Based on sequence similarity, Cik1 is predicted to contain a motor homology domain. Thus, Katherine's research should provide valuable insight into the common functional asymmetry that manifests itself in non processive molecular motors. NMR will be used to synthesize a high capacity strep column which will aid in the purification of Kar3-Vik1 and Kar3-Cik1 heterodimers.