TY - JOUR T1 - Characterization of <em>P. falciparum</em> dipeptidyl aminopeptidase 3 specificity identifies different amino acid preferences between peptide-based substrates and inhibitors JF - bioRxiv DO - 10.1101/246124 SP - 246124 AU - Edgar Deu AU - Laura E. de Vries AU - Mateo Isidrio Sanchez AU - Katarzyna Groborz AU - Laurie Kuppens AU - Marcin Poreba AU - Christine Lehmann AU - Fang Yuan AU - Shirin Arastu-Kapur AU - Matthew Bogyo AU - Marcin Drag Y1 - 2018/01/01 UR - http://biorxiv.org/content/early/2018/01/11/246124.abstract N2 - Dipeptidyl aminopeptidases (DPAPs) are druggable cysteine proteases that cleave dipeptides from the N-terminus of proteins and oligopeptides. Plasmodium DPAPs have been shown to be important for the asexual replication of the malaria parasite and are therefore potential antimalarial targets. DPAP1 seems to be important for parasite growth within infected red blood cells, and DPAP3 plays a critical role in the invasion of erythrocytes by the malaria parasite. An inhibitor able to block both of these proteases will target the parasite at different developmental stages thus making the emergence of drug resistance more difficult. Understanding the substrate specificity of these proteases is important to understand their molecular function and to help develop potent and selective inhibitors. In this study, we used peptide-based libraries of substrates to determine the specificity of DPAP3 and compared it to that of DPAP1 and human cathepsin C (mammalian DPAP homologue). We then used the structure activity relationships information from these screens to develop optimal DPAP3 fluorogenic substrates as well as highly specific DPAP1 and DPAP3 inhibitors. Interestingly, while the substrate specificity of a protease is often used to develop potent inhibitors, in this study we show that equally potent and highly specific inhibitors can be developed based on the structure of poor substrates. Overall, this study illustrates that focusing the development of peptidic inhibitors solely on the substrate specificity of a protease might overlook important structural features that can be exploited to developed highly potent and selective compounds. ER -