Voltage-gated hydrogen channel 1
regulation of reactive oxygen species biosynthetic process
Role of human Hv1 channels in sperm capacitation and white blood cell respiratory burst established by a designed peptide inhibitor.
Using a de novo peptide inhibitor, Corza6 (C6), we demonstrate that the human voltage-gated proton channel (hHv1) is the main pathway for H<sup>+</sup> efflux that allows capacitation in sperm and permits sustained reactive oxygen species (ROS) production in white blood cells (WBCs). C6 was identified by a phage-display strategy whereby ∼1 million novel peptides were fabricated on an inhibitor cysteine knot (ICK) scaffold and sorting on purified hHv1 protein. Two C6 peptides bind to each dimeric channel, one on the S3-S4 loop of each voltage sensor domain (VSD). Binding is cooperative with an equilibrium affinity (<i>K</i><sub>d</sub>) of ∼1 nM at -50 mV. As expected for a VSD-directed toxin, C6 inhibits by shifting hHv1 activation to more positive voltages, slowing opening and speeding closure, effects that diminish with membrane depolarization.