Mutation of Asn11 does not impair the CXCR4-mediated HIV-1 infection [95,96]; however, a Asn11-to-Glu11 mutation leads to enhanced binding of both CXCR4-specific and dual-tropic (CCR5 and CXCR4) HIV-1 isolates [78,96]. Here, CXCR4 is linked to HIV-1 infection.