https://www.selleckchem.com/products/pirfenidone.html Over the past decade, we described a novel tumour targeted approach that sought to design "combi-molecules" to hit two distinct targets in tumour cells. Here, to generate small combi-molecules with strong DNA damaging potential while retaining EGFR inhibitory potency, we developed the first synthetic strategy to access the 6-N, N-disubstituted quinazoline scaffold and designed JS61 to possess a nitrogen mustard function directly attached to the 6-position of the quinazoline ring. We compared its biological activity with that of structures containing either a hemi mustard or a non-alkylating substituent. Surprisingly, the results showed that JS61, while capable of inducing strong DNA damage, exhibited moderate EGFR inhibitory potency. In contrast, "combi-molecules" with no bulky substituent at the N-6 position (e.g. ZR2002 and JS84) showed stronger EGFR and growth inhibitory potency than JS61 in a panel of lung cancer cells. To rationalize these results, X-ray crystallography and molecular modeling studies were undertaken, and the data obtained indicated that bulkiness of the 6-N,N-disubstituted moieties hinder its binding to the ATP site and affects binding reversibility. The l-cysteine is crucial for growth, survival, defense against oxidative stress, and pathogenesis of Entamoeba histolytica. The de novo biosynthesis of l-cysteine in E. histolytica, has a two-step pathway, where O-acetylserine sulfhydrylase (OASS) catalyses the last step by converting OAS to l-cysteine. This pathway is absent in humans and hence represents a promising target for novel therapeutics. E. histolytica expresses three isoforms of OASS and knockdown studies showed the importance of these enzymes for the survival of the pathogen. Here, we report the crystal structure of OASS isoform 3 from E. histolytica to 1.54 Å resolution. The active site geometries and kinetics of EhOASS3 and EhOASS1 structures were found to be very similar. Small-