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We report ultrasensitive Ca(2+) indicators, yellow cameleon-Nano (YC-Nano), developed by engineering the Ca(2+)-sensing domain of a genetically encoded Ca(2+) indicator, YC2.60 or YC3.60. Their high Ca(2+) affinities (K(d) = 15-140 nM) and large signal change (1,450%) enabled detection of subtle Ca(2+) transients associated with intercellular signaling(More)
We have used protein engineering to expand the palette of genetically encoded calcium ion (Ca(2+)) indicators to include orange and improved red fluorescent variants, and validated the latter for combined use with optogenetic activation by channelrhodopsin-2 (ChR2). These indicators feature intensiometric signal changes that are 1.7- to 9.7-fold improved(More)
All biological reactions depend on the diffusion and re-localization of biomolecules. Our understanding of biological processes requires accurate measurement of biomolecule mobility in living cells. Currently, approaches for investigating the mobility of biomolecules are generally restricted to measuring either fast or slow diffusion kinetics. We describe(More)
For understanding the precise mechanisms of molecular recognition of proteins, three-dimensional structural analyses of the protein-protein complexes are essential. For this purpose, a new method to reveal complex structures was developed with the assistance of saturation transfer (SAT) and residual dipolar coupling (RDC) by heteronuclear NMR experiments,(More)
The use of fluorescent proteins has revolutionized our understanding of biological processes. However, the requirement for external illumination precludes their universal application to the study of biological processes in all tissues. Although light can be created by chemiluminescence, light emission from existing chemiluminescent probes is too weak to use(More)
TATA-binding protein (TBP)-interacting protein from the hyperthermophilic archaeon Thermococcus kodakaraensis strain KOD1 (Tk-TIP26) is a possible transcription regulatory protein in Thermococcales. Here, we report the crystal structure of Tk-TIP26 determined at 2.3 A resolution with multiple-wavelength anomalous dispersion (MAD) method. The overall(More)
We report a pH-insensitive and photostable ultramarine fluorescent protein, Sirius, with an emission peak at 424 nm, the shortest emission wavelength among fluorescent proteins reported to date. The pH-insensitivity of Sirius allowed prolonged visualization of biological events in an acidic environment. Two fluorescence resonance energy transfer (FRET)(More)
Chromophore-assisted light inactivation (CALI) is a powerful technique for acute perturbation of biomolecules in a spatio-temporally defined manner in living specimen with reactive oxygen species (ROS). Whereas a chemical photosensitizer including fluorescein must be added to specimens exogenously and cannot be restricted to particular cells or sub-cellular(More)
Genetically encoded fluorescent indicators for bioimaging are powerful tools for visualizing biological phenomena in specified cell types or cellular compartments. However, available gene promoters or localization sequences are not applicable for visualizing all expression events. Furthermore, a visualization technique focusing on single cells or cellular(More)
The structural modification of dendritic spines plays a critical role in synaptic plasticity. CaMKII is a pivotal molecule involved in this process through both kinase-dependent and independent structural functions, but the respective contributions of these two functions to the synaptic plasticity remain unclear. We demonstrate that the transient interplay(More)