1.A.68.1.1
The viral small hydrophobic protein (V-SHP; hRSV-SH) of 64 aas with 1 TMS,  It forms a pentameric ion conducting pore in the membrane (Surya and Torres 2015) that transports monovalent cations (Hyser and Estes 2015). The SH protein has two protonatable His residues in its transmembrane domain that are oriented facing the lumen of the channel.  Their protonation may serve as a pH sensor, to promote electrostatic repulsion and reduced oligomer stability at low pH (Surya and Torres 2015).  Pyronin B can reduce SH channel activity, and its likely binding site on the SH protein channel has been identified. Black lipid membrane experiments confirmed that protonation of both histidine residues reduces stability and channel activity (Li et al. 2014).  Water transport was observed with histidine residues of five chains (His22 and His51) playing a key role in pore permeability (Araujo et al. 2016). The assembly of the transmembrane domains of viral channel-forming proteins and peptide drug screening has been achieved using a docking approach (Huang and Fischer 2022).