A single amino acid change in Ca V 1.2 channels eliminates the permeation and gating differences between Ca 2+ and Ba 2+

Zhe Li, Xianming Wang, Guofeng Gao, Dongmei Qu, Buwei Yu, Congxin Huang, Keith S. Elmslie, Blaise Peterson

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Abstract

Glutamate scanning mutagenesis was used to assess the role of the calcicludine binding segment in regulating channel permeation and gating using both Ca 2+ and Ba 2+ as charge carriers. As expected, wild-type Ca V 1.2 channels had a Ba 2+ conductance ~2× that in Ca 2+ (G Ba /G Ca = 2) and activation was ~10 mV more positive in Ca 2+ vs. Ba 2+ . Of the 11 mutants tested, F1126E was the only one that showed unique permeation and gating properties compared to the wild type. F1126E equalized the Ca V 1.2 channel conductance (G Ba /G Ca = 1) and activation voltage dependence between Ca 2+ and Ba 2+ . Ba 2+ permeation was reduced because the interactions among multiple Ba 2+ ions and the pore were specifically altered for F1126E, which resulted in Ca 2+ -like ionic conductance and unitary current. However, the high-affinity block of monovalent cation flux was not altered for either Ca 2+ or Ba 2+ . The half-activation voltage of F1126E in Ba 2+ was depolarized to match that in Ca 2+ , which was unchanged from that in the wild type. As a result, the voltages for half-activation and half-inactivation of F1126E in Ba 2+ and Ca 2+ were similar to those of wild-type in Ca 2+ . This effect was specific to F1126E since F1126A did not affect the half-activation voltage in either Ca 2+ or Ba 2+ . These results indicate that residues in the outer vestibule of the Ca V 1.2 channel pore are major determinants of channel gating, selectivity, and permeation.

Original languageEnglish (US)
Pages (from-to)23-33
Number of pages11
JournalJournal of Membrane Biology
Volume233
Issue number1-3
DOIs
StatePublished - Feb 1 2010

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Monovalent Cations
Mutagenesis
Glutamic Acid
Ions
Amino Acids
calcicludin

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Physiology
  • Cell Biology

Cite this

Li, Zhe ; Wang, Xianming ; Gao, Guofeng ; Qu, Dongmei ; Yu, Buwei ; Huang, Congxin ; Elmslie, Keith S. ; Peterson, Blaise. / A single amino acid change in Ca V 1.2 channels eliminates the permeation and gating differences between Ca 2+ and Ba 2+ In: Journal of Membrane Biology. 2010 ; Vol. 233, No. 1-3. pp. 23-33.
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abstract = "Glutamate scanning mutagenesis was used to assess the role of the calcicludine binding segment in regulating channel permeation and gating using both Ca 2+ and Ba 2+ as charge carriers. As expected, wild-type Ca V 1.2 channels had a Ba 2+ conductance ~2× that in Ca 2+ (G Ba /G Ca = 2) and activation was ~10 mV more positive in Ca 2+ vs. Ba 2+ . Of the 11 mutants tested, F1126E was the only one that showed unique permeation and gating properties compared to the wild type. F1126E equalized the Ca V 1.2 channel conductance (G Ba /G Ca = 1) and activation voltage dependence between Ca 2+ and Ba 2+ . Ba 2+ permeation was reduced because the interactions among multiple Ba 2+ ions and the pore were specifically altered for F1126E, which resulted in Ca 2+ -like ionic conductance and unitary current. However, the high-affinity block of monovalent cation flux was not altered for either Ca 2+ or Ba 2+ . The half-activation voltage of F1126E in Ba 2+ was depolarized to match that in Ca 2+ , which was unchanged from that in the wild type. As a result, the voltages for half-activation and half-inactivation of F1126E in Ba 2+ and Ca 2+ were similar to those of wild-type in Ca 2+ . This effect was specific to F1126E since F1126A did not affect the half-activation voltage in either Ca 2+ or Ba 2+ . These results indicate that residues in the outer vestibule of the Ca V 1.2 channel pore are major determinants of channel gating, selectivity, and permeation.",
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A single amino acid change in Ca V 1.2 channels eliminates the permeation and gating differences between Ca 2+ and Ba 2+ . / Li, Zhe; Wang, Xianming; Gao, Guofeng; Qu, Dongmei; Yu, Buwei; Huang, Congxin; Elmslie, Keith S.; Peterson, Blaise.

In: Journal of Membrane Biology, Vol. 233, No. 1-3, 01.02.2010, p. 23-33.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A single amino acid change in Ca V 1.2 channels eliminates the permeation and gating differences between Ca 2+ and Ba 2+

AU - Li, Zhe

AU - Wang, Xianming

AU - Gao, Guofeng

AU - Qu, Dongmei

AU - Yu, Buwei

AU - Huang, Congxin

AU - Elmslie, Keith S.

AU - Peterson, Blaise

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N2 - Glutamate scanning mutagenesis was used to assess the role of the calcicludine binding segment in regulating channel permeation and gating using both Ca 2+ and Ba 2+ as charge carriers. As expected, wild-type Ca V 1.2 channels had a Ba 2+ conductance ~2× that in Ca 2+ (G Ba /G Ca = 2) and activation was ~10 mV more positive in Ca 2+ vs. Ba 2+ . Of the 11 mutants tested, F1126E was the only one that showed unique permeation and gating properties compared to the wild type. F1126E equalized the Ca V 1.2 channel conductance (G Ba /G Ca = 1) and activation voltage dependence between Ca 2+ and Ba 2+ . Ba 2+ permeation was reduced because the interactions among multiple Ba 2+ ions and the pore were specifically altered for F1126E, which resulted in Ca 2+ -like ionic conductance and unitary current. However, the high-affinity block of monovalent cation flux was not altered for either Ca 2+ or Ba 2+ . The half-activation voltage of F1126E in Ba 2+ was depolarized to match that in Ca 2+ , which was unchanged from that in the wild type. As a result, the voltages for half-activation and half-inactivation of F1126E in Ba 2+ and Ca 2+ were similar to those of wild-type in Ca 2+ . This effect was specific to F1126E since F1126A did not affect the half-activation voltage in either Ca 2+ or Ba 2+ . These results indicate that residues in the outer vestibule of the Ca V 1.2 channel pore are major determinants of channel gating, selectivity, and permeation.

AB - Glutamate scanning mutagenesis was used to assess the role of the calcicludine binding segment in regulating channel permeation and gating using both Ca 2+ and Ba 2+ as charge carriers. As expected, wild-type Ca V 1.2 channels had a Ba 2+ conductance ~2× that in Ca 2+ (G Ba /G Ca = 2) and activation was ~10 mV more positive in Ca 2+ vs. Ba 2+ . Of the 11 mutants tested, F1126E was the only one that showed unique permeation and gating properties compared to the wild type. F1126E equalized the Ca V 1.2 channel conductance (G Ba /G Ca = 1) and activation voltage dependence between Ca 2+ and Ba 2+ . Ba 2+ permeation was reduced because the interactions among multiple Ba 2+ ions and the pore were specifically altered for F1126E, which resulted in Ca 2+ -like ionic conductance and unitary current. However, the high-affinity block of monovalent cation flux was not altered for either Ca 2+ or Ba 2+ . The half-activation voltage of F1126E in Ba 2+ was depolarized to match that in Ca 2+ , which was unchanged from that in the wild type. As a result, the voltages for half-activation and half-inactivation of F1126E in Ba 2+ and Ca 2+ were similar to those of wild-type in Ca 2+ . This effect was specific to F1126E since F1126A did not affect the half-activation voltage in either Ca 2+ or Ba 2+ . These results indicate that residues in the outer vestibule of the Ca V 1.2 channel pore are major determinants of channel gating, selectivity, and permeation.

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