soblidotin [ N(2)-(N,N-dimethyl-valyl)-N-(2-methoxy-4-(2-(1-methoxy-2-methyl-3-oxo-3-((2-phenylethyl)amino)propyl)-1-pyrrolidinyl)-1-(1-methylpropyl)-4-oxobutyl)-N-methyl-valinamide,TZT 1027,TZT-1027,auristatin PE ] a dolastatin 10 derivative; RN refers to (2S-(1(1R*(R*),2S*),2R*(1S*,2S*)))-isomer; structure given in first source