부산대학교 도서관

Neurobiologists widely use green genetically encoded calcium indicators (GECIs) for visualization of neuronal activity. Among them, ratiometric GECIs allow imaging of both active and non-active neuronal populations. However, they are not popular, since their properties are inferior to intensiometric GCaMP series of GECIs. The most characterized and developed ratiometric green GECI is FGCaMP7. However, the dynamic range and sensitivity of its large Stock's shift green (LSS-Green) form is significantly lower than its Green form and its molecular design is not optimal. To address these drawbacks, we engineered a ratiometric green calcium indicator, called FNCaMP, which is based on bright mNeonGreen protein and calmodulin from A. niger and has optimal NTnC-like design. We compared the properties of the FNCaMP and FGCaMP7 indicators in vitro, in mammalian cells, and in neuronal cultures. Finally, we obtained and analyzed X-ray structure of the FNCaMP indicator. • A new ratiometric green calcium indicator NCaMP allows visualization of neurons both at rest and during their activity. • Crystal structure of the ratiometric NCaMP calcium indicator reveals key features of its function. • NTnC-like design of FNCaMP ensures that its properties are preserved in fusion constructs with other proteins. • Calmodulin from the A. niger fungus ensures the inertness of FNCaMP to components of the intracellular environment. [ABSTRACT FROM AUTHOR]