Mechanisms of macromolecular protease inhibitors.

摘要: Proteolytic enzymes are ubiquitous in all organisms and constitute 2–4% of the encoded gene products. They critical for diverse biological processes such as digestion, blood clotting, host defense, pathogenic infection, viral replication, wound healing, disease progression, to name a few. Because proteases trigger an irreversible event - cleavage protein their activity must be tightly controlled. Dysregulated proteolytic causes disruption homeostatic balance system can result any number poor outcomes. As result, nature has developed strategies control proteolysis, including spatial temporal regulation, zymogen activation protease degradation, through inhibition by macromolecular inhibitors. Somewhat surprisingly, relatively few design principles underlie mechanisms myriad range Significant engineering efforts have gone into modifying improving inhibitor potency specificity, large extent, same that work well naturally occurring inhibitors proved valuable laboratory. This review aims survey which function. To do this, been divided categories based on mechanism order illustrate small combined develop new effective These divisions not strict, many could grouped classes. The list presented here is exhaustive its treatment inhibitors, but illustrative ways inhibited. For more information genome-wide mining,[1] mechanism,[2] pre-clinical inhibition,[3] drug discovery efforts,[4] reader directed excellent reviews written recent years. Figure 1 provides overview basic substrate nomenclature will used this review. Figure 1 (A) Diagram active site. A cleaves peptide at scissile bond, specificity subsites, determine specificity. Substrates bind with non-prime residues N-terminal side ... Competitive Inhibitors The vast majority competitive Despite divergent targets different inhibition, most portion site substrate-like manner (Figure 2). This paradigm potent because related often show high degree homology site, binding leads potently inhibit than one target protease. promiscuity evidenced fact there 115 annotated human responsible regulating 612 known proteases. Though these numbers change refinement families achieved, ratio approximately five likely remain constant.[5] Figure 2 Competitive, (A) Inhibitors manner. Peptide extensions interact catalytic (rectangle). Crystal structures ... The thoroughly studied standard (or Canonical, or Laskowski mechanism) serine proteases.[6] include Kazal, Kunitz, Bowman-Birk family lock-and-key fashion. Standard insert reactive loop protease, complementary binds extended β-sheet enzyme While bound “scissile bond” hydrolyzed very slowly, products released, amide bond re-ligated.[7,8] efficient way proteases, thus structurally disparate scaffolds create However, tend broad within sub-classes example, bovine pancreatic trypsin (BPTI) efficiently inhibits almost trypsin-fold P1-Arg sub-nanomolar potency, also chymotrypsin (Phe P1 specificity) KI 10 nM[9] 2B). The block access strictly Instead they subsites non-catalytically competent differentiates them from like get interactions proteases. The cystatins, superfamily proteins papain-like cysteine classic example 2A, 2C). cystatins wedge-like face consisting N-terminus two hairpin loops V-shaped S3-S1 pockets manner, then turns away out prime-side energy interaction. Thus, both prime sides occupied, no actually made machinery enzyme.[10] The four tissue metalloproteases (TIMPs) dozens extracellular 2B). two-step similar cystatins. TIMPs N-termini P1–P3’ coordinate Zn2+ ion, exclude water molecule Meanwhile second TIMP P3 P2 pockets, MMP. similarities mechanistic architecture between (hairpin pockets), interfere MMPs chelating Zn2+.[11]