(2Z)-2-[(2E,4E)-5-[3-[6-[2-[[(2S)-2-[[(2S)-2-benzamido-3-cyclohexylpropanoyl]amino]-4-[[1-[2-[3-(2,3-dihydroindol-1-ium-1-ylidene)-6-(2,3-dihydroindol-1-yl)xanthen-9-yl]phenyl]sulfonylpiperidine-4-carbonyl]amino]butanoyl]amino]ethylamino]-6-oxohexyl]-1,1-dimethyl-6,8-disulfobenzo[e]indol-3-ium-2-yl]penta-2,4-dienylidene]-3-ethyl-1,1-dimethylbenzo[e]indole-6,8-disulfonic acid