02795nas a2200265   4500008004100000022001400041245014500055210006900200260000800269300001400277490000900291520187200300653001902172653001602191653001702207653002302224653001802247100002702265700002202292700002002314700002002334700002402354700002002378856013102398       2019                        eng d  a0304-416500aPhyto-inspired cyclic peptides derived from plant Pin-II type protease inhibitor reactive center loops for crop protection from insect pests0 aPhytoinspired cyclic peptides derived from plant PinII type prot  cAUG  a1254-12620 v18633 a<p>Background: Natural defence of plants against insect pests involves protease inhibitors (PIs) that interfere with insect digestive proteases. Pin-II type plant PIs are wound inducible upon insect damage and possess multiple inhibitory repeat domains that can inhibit trypsin and chymotrypsin-like proteases in the insect midgut. Yet, their agricultural ex-vivo application is limited due to large molecular size and environmental instability, which could be overcome by small peptides. Methods: Bicyclic peptides were designed by grafting Pin-II PIs derived reactive center loop (RCL) on synthetic tris(bromomethyl)benzene scaffold. In vitro binding with trypsin-like proteases was evaluated by biochemical and biophysical assays, followed by molecular dynamics simulations. In vivo effects on two major lepidopteran insect pests, Helicoverpa armigera and Spodoptera litura were studied upon feeding with peptide treated leaves. Affinity based pull down assays were used to identify target proteins in insect gut. Results: Bicyclic RCLs showed ten-fold enhanced protease inhibition compared to their linear counterparts. They exhibited feeding deterrence and growth reduction of lepidopteran insects. Bicyclic peptides predominantly interact with midgut serine proteases. Possible binding modes involve simultaneous interaction with the active site and specificity-determining residues of insect gut trypsin. Conclusion: Bicyclic peptides are potent inhibitors of serine proteases in the insect midgut. They cause feeding aversion and larval growth retardation. Bi-domain cyclic peptides interact with two sites on trypsin, leading to enhanced efficacy over linear RCL peptides. General significance: Bicyclic peptides mimic natural PIs by inhibiting insect proteases leading to growth reduction, thus, could be used as pest control molecules in agriculture.</p>
10aCyclic peptide10aLepidoptera10aPest control10aprotease inhibitor10aReactive loop1 aSailthedkar, Nidhi, S.1 aJoshi, Rakesh, S.1 aYadav, Amit, K.1 aSeal, Shubhendu1 aFernandes, Moneesha1 aGiri, Ashok, P.  uhttps://library.ncl.res.in/content/phyto-inspired-cyclic-peptides-derived-plant-pin-ii-type-protease-inhibitor-reactive-center