CXCR4 and HIV-1 infection: This peptide, named CX4-M1, is able to discriminate between CXCR4- and CCR5-recognizing gp120 (Möbius et al., 2012) and V3-loop peptides mimicking the corresponding binding site on gp120 (Groß et al., 2013), and also inhibits HIV-1 infection of susceptible target cells in a CXCR4-specific manner (Möbius et al., 2012; Groß et al., 2015a).