The role and structure of the carboxyl-terminal domain of the human voltage-gated proton channel Hv1.
The voltage-gated proton channel Hv1 has a voltage sensor domain but lacks a pore domain. Although the C-terminal domain of Hv1 is known to be responsible for dimeric architecture of the channel, its role and structure are not known. We report that the full-length Hv1 is mainly localized in intracellular compartment membranes rather than the plasma membrane. Truncation of either the N or C terminus alone or both together revealed that the N-terminal deletion did not alter localization, but deletion of the C terminus either alone or together with the N terminus resulted in expression throughout the cell. These results indicate that the C terminus is essential for Hv1 localization but not the N terminus. In the 2.0 A structure of the C-terminal domain, the two monomers form a dimer via a parallel alpha-helical coiled-coil, in which one chloride ion binds with the Neta atom of Arg(264). A pH-dependent structural change of the protein has been observed, but it remains a dimer irrespective of pH value.
Key Laboratory of Bioactive Materials, Ministry of Education, College of Physics Science, Nankai University, Tianjin 300071, China. shujieli@nankai.edu.cn
Shu Jie
SJ
Li
Qing
Q
Zhao
Qiangjun
Q
Zhou
Hideaki
H
Unno
Yujia
Y
Zhai
Fei
F
Sun
D002451:Cell Compartmentation; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007473:Ion Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D055672:Static Electricity
C510235:HVCN1 protein, human; D007473:Ion Channels; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins