(A) Chemical structures of novel BRD4 inhibitors ZL0420 and ZL0454. (B). Binding mode of ZL0420 (yellow) with BRD4 BD1 in ribbon representation. The highlighted residues are Asn140 (N140), Tyr97 (Y97), Pro82 (P82), Trp81 (W81) and Lys91 (K91). (C). Binding mode of ZL0454 (magenta) with BRD4 BD1 in ribbon representation. (D). Superimposition of ZL0420 (green) and ZL0454 (yellow) docked into BRD4 BD1 in the form of surface representation. WPF (Trp81-Pro82-Phe83) shelf is highlighted in magenta and part of ZA loop is colored orange. Asn, Asparagine; Tyr, Tyrosine; Pro, Proline; Trp, Tryptophan; Lys, Lysine.