STUDIES OF CONFORMATIONAL CHANGES IN SOLUBLE GUANYLATE CYCLASE

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。 可溶性鸟苷环化酶(SGC)是细胞内主要的一氧化氮(NO)受体，是一种150kD的异源二聚体蛋白。NO与β亚基N末端区域的血红素结合，刺激cGMP的产生，导致NO依赖的信号级联反应。体外研究表明，当配体结合时，可能会发生变构构象变化。除了生理配体NO，还有以YC-1为代表的与一氧化碳(CO)协同作用的效应配体。我们要求光束时间对可溶性鸟苷环化酶进行小角X射线散射研究，以表征与配体结合相关的构象变化。人和Manduca sexta sGC的几个不同的结构域和结构已经通过重组方法表达出来，并且已经或将在不久的将来获得。初步的分析性超速离心研究表明，构象变化大到足以用SAXS表征，并且在离心实验的条件下蛋白质不会明显聚集。

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. Soluble guanylate cyclase (sGC), a 150 kD heterodimeric protein, is the primary nitric oxide (NO) receptor in the cell. NO binds to heme in the N-terminal domain of the beta subunit, stimulates the production of cGMP and leads to NO-dependent signaling cascades. In vitro studies have shown that a probably allosteric conformational change takes place when ligands bind. In addition to the physiological ligand NO, there are effector ligands, typified by YC-1 that act in concert with carbon monoxide (CO). We request beam time to perform small angle x-ray scattering studies on soluble guanylate cyclase in order to characterize ligand binding associated conformational changes. Several different domains and constructs of both human and Manduca sexta sGC have been expressed by recombinant methods and are available, or will become available in the near future. Preliminary analytical ultracentrifugation studies demonstrate that the conformational change is large enough to be characterized by SAXS and that the protein does not aggregate significantly under the conditions of the centrifugation experiment.