The present invention relates to a method of designing an inhibitor of the binding of HIV (human immunodeficiency virus) glycoprotein (gp)120 to a CD4-receptor or to the integrin alpha4 beta7 (a4b7), the method comprising the molecular modelling of a compound such that the modelled compound interacts in silico with at least two amino acid residues comprised in six motifs within the 3-dimensional structure of said gp120 of HIV or within a peptidomimetic reflecting the 3-dimensional structure of said gp120 of HIV, wherein said interaction between said at least two amino acid residues and said compound is characterized by an interatomic distance of less than 8 Angstroms, wherein a first motif of said six motifs comprises the amino acid sequence DIISLWDQSLKPCVKLT or a variant thereof wherein a second motif of said six motifs comprises the amino acid sequence N VSTVQCTHG I RP WSTQLLLNGSLAE or a variant thereof wherein a third motif of said six motifs comprises the amino acid sequence SGGDPEIVMHSFNCGGEFFYCN or a variant thereof wherein a fourth motif of said six motifs comprises the amino acid sequence CPKISFEP or a variant thereof wherein a fifth motif of said six motifs comprises the amino acid sequence FRPGGGDMRDNWRSELYKYKVV or a variant thereof and wherein a sixth motif of said six motifs comprises the amino acid sequence CSS or a variant thereof, said gp120 of HiV comprising or consisting of (i) the sequence of SEQ ID NO: 2 (ii) the sequence encoded by the sequence of SEQ ID NO: 1 (iii) a sequence being at least 50% identical to the sequence of SEQ ID NO: 2 or to the sequence encoded by the sequence of SEQ ID NO: 1 or (iv) a sequence encoded by a sequence being at least 50% identical to the sequence of SEQ ID NO: 1, wherein said sequence of (iii) or (iv) comprises or encodes said motifs or variants thereof. Also, the invention relates to a method of identifying an inhibitor of the binding of HIV gp120 to CD4 or the integrin a4b7, compounds that inhibit the binding of
