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 HIV gp120 to CD4 or the integrin a4b7, a method of decreasing thermal motion of a tunnel within HiV gp120, compounds for use in preventing or treating a HlV-infection and/or a disease associated with a HlV-infection and a pharmaceutical composition comprising any of the above compounds or inhibitors. Finally, the invention also relates to a tunnel within gp120. In this specification, a number of documents including manufacturer's manuals is cited. The disclosure of these documents, while not considered relevant for the patentability of this invention, is herewith incorporated by reference in its entirety. More specifically, all referenced documents are incorporated by reference to the same extent as if each individual document was specifically and individually indicated to be incorporated by reference. Human immunodeficiency virus (HIV) is a retrovirus belonging to the primate lentiviruses that can lead upon successful infection to a condition termed acquired immunodeficiency syndrome (AIDS). Said condition is characterized in that the immune system begins to fail and therefore the patient's body becomes increasingly susceptible to secondary and/or recurring infections. The infection with HIV occurs by, e.g., transfer of blood, semen, vaginal fluid and also breast milk. Due to the presence of unbound infectious virus particles in body fluids the rate of infection is high. In particular, sexual intercourse and transmission from infected mothers to their babies as we!l as feeding with breast milk account for a majority of new HIV cases.