Gerrit H U Lamm, Dmitrii Zabelskii, Taras Balandin, Valentin Gordeliy, Josef Wachtveitl
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引用次数: 0
Abstract
The viral rhodopsin 1 subfamily consists of microbial rhodopsins, such as VirChR1, with a light-gated cation channeling functionality, which is inhibited by calcium. For VirChR1, S14, E54, and N225 have been proposed as key residues for calcium binding. They form a highly conserved SEN-triad in channelrhodopsins near the functionally important central gate. Here, we present a time-resolved UV/vis spectroscopic study on the VirChR1 variants S14A, E54A, and N225A in a calcium-dependent manner. Comparison with the calcium-associated effects observed for the wild type shed light on the role of the respective residues for the calcium interaction. While S14A shows less pronounced, yet similar, signals, indicative of a reduced calcium affinity, E54A exhibits nearly calcium-independent photocycle kinetics, highlighting its crucial role for calcium binding. The N225A variant shows altered photocycle kinetics, in both the absence and presence of calcium, demonstrating its critical role in the formation of the functionally important central gate in VirChR1.
期刊介绍:
An essential criterion for acceptance of research articles in the journal is that they provide new physical insight. Please refer to the New Physical Insights virtual issue on what constitutes new physical insight. Manuscripts that are essentially reporting data or applications of data are, in general, not suitable for publication in JPC B.