1.A.68 The Viral Small Hydrophobic Protein (V-SHP) Family

The small hydrophobic (SH) protein from the human respiratory syncytial virus (hRSV) is a glycoprotein of approximately 64 amino acids with one putative alpha-helical transmembrane domain. Although SH protein is important for viral infectivity, its exact role during viral infection is not clear. Gan et al., 2008 studied the secondary structure, orientation, and oligomerization of the transmembrane domain of SH (SH-TM) in the presence of lipid bilayers. Only one oligomer, a pentamer, was observed.  SH-TM is probably alpha-helical.

Conductance studies of SH-TM indicated ion channel activity which is cation selective, and inactive below the predicted pK(a) of histidine. Thus, the transmembrane domain of the SH protein forms pentameric alpha-helical bundles that form cation-selective ion channels in planar lipid bilayers. Gan et al., 2008 suggest a model for this pore.

The generalized reaction catalyzed by V-SHP is:

ions (in) ↔ ions (out)