Amino acid sequence comparisons between the capsid proteins of several human rhinovirus (HRV) serotypes identified residues potentially involved in the discrimination between the major and the minor group receptors. Amino acids conserved within minor group HRVs were substituted in a full-length cDNA clone of HRV2 for those found at equivalent positions in major group HRVs. Transfection of HeLa cells with RNAs transcribed from seven individual mutated cDNAs gave rise to only two viable viruses; growth characteristics and affinity for the minor group receptor of both were unchanged compared to wild-type. Similar mutations in HRV14 were previously shown to alter the affinity for its receptor; the contact sites between the minor group viruses and the respective receptor may therefore be different.