| Autor: |
Xiaomin Ou, Jianli Guo, Longfei Wang, Hanting Yang, Xiuying Liu, Jianyuan Sun, Zhenfeng Liu |
| Jazyk: |
angličtina |
| Rok vydání: |
2017 |
| Předmět: |
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| Zdroj: |
BMC Biology, Vol 15, Iss 1, Pp 1-17 (2017) |
| Druh dokumentu: |
article |
| ISSN: |
1741-7007 |
| DOI: |
10.1186/s12915-017-0372-8 |
| Popis: |
Abstract Background Trimeric intracellular cation (TRIC) channels are crucial for Ca2+ handling in eukaryotes and are involved in K+ uptake in prokaryotes. Recent studies on the representative members of eukaryotic and prokaryotic TRIC channels demonstrated that they form homotrimeric units with the ion-conducting pores contained within each individual monomer. Results Here we report detailed insights into the ion- and water-binding sites inside the pore of a TRIC channel from Sulfolobus solfataricus (SsTRIC). Like the mammalian TRIC channels, SsTRIC is permeable to both K+ and Na+ with a slight preference for K+, and is nearly impermeable to Ca2+, Mg2+, or Cl–. In the 2.2-Å resolution K+-bound structure of SsTRIC, ion/water densities have been well resolved inside the pore. At the central region, a filter-like structure is shaped by the kinks on the second and fifth transmembrane helices and two nearby phenylalanine residues. Below the filter, the cytoplasmic vestibule is occluded by a plug-like motif attached to an array of pore-lining charged residues. Conclusions The asymmetric filter-like structure at the pore center of SsTRIC might serve as the basis for the channel to bind and select monovalent cations. A Velcro-like plug-pore interacting model has been proposed and suggests a unified framework accounting for the gating mechanisms of prokaryotic and eukaryotic TRIC channels. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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