@article { ISI:000361402900006, title = {Cathepsins of lepidopteran insects: aspects and prospects}, journal = {Insect Biochemistry and Molecular Biology}, volume = {64}, year = {2015}, month = {SEP}, pages = {51-59}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Molecular understanding of lepidopteran physiology has revealed that proteases consist of one of the central regulatory/reacting system for insect growth and survival. Among the various proteases, cathepsins are the most crucial cellular proteases, which play vital roles during insect development. In the present review, we have discussed various aspects of the lepidopteran insect cathepsins, emphasizing their roles in processes like development, growth, metamorphosis, apoptosis and immunity. Cathepsins are categorized into different types on the basis of their sequence diversification, leading to variation in structure and catalytic function. Cathepsins exhibit tissue and stage specific expression pattern which is fine-tuned by a delicate balance of expression, compartmentalization, zymogen activation, inhibition by protein inhibitors and degradation. The indispensability of cathepsins as cellular proteases in the above mentioned processes proposes them as novel targets for designing effective and specific insect controlling strategies. (C) 2015 Elsevier Ltd. All rights reserved.

}, keywords = {Apoptosis, Cathepsin, Cysteine/aspartate protease, Development, Lepidoptera, Pest control, Stress response}, issn = {0965-1748}, doi = {10.1016/j.ibmb.2015.07.005}, author = {Saikhedkar, Nidhi and Summanwar, Aarohi and Joshi, Rakesh S. and Giri, Ashok P.} } @article {46049, title = {Phyto-inspired cyclic peptides derived from plant Pin-II type protease inhibitor reactive center loops for crop protection from insect pests}, journal = {Biochimica ET Biophysica Acta-General Subjects}, volume = {1863}, year = {2019}, month = {AUG}, pages = {1254-1262}, type = {Article}, abstract = {

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.

}, keywords = {Cyclic peptide, Lepidoptera, Pest control, protease inhibitor, Reactive loop}, issn = {0304-4165}, doi = {10.1016/j.bbagen.2019.05.003}, author = {Sailthedkar, Nidhi S. and Joshi, Rakesh S. and Yadav, Amit K. and Seal, Shubhendu and Fernandes, Moneesha and Giri, Ashok P.} } @article {48694, title = {Domain shuffling and site-saturation mutagenesis for the enhanced inhibitory potential of amaranthaceae α-amylase inhibitors}, journal = {Protein Journal}, volume = {42}, year = {2023}, month = {OCT}, pages = {519-532}, type = {Article}, abstract = {

Amaranthaceae a-amylase inhibitors (AAIs) are knottin-type proteins with selective inhibitory potential against coleopteran a-amylases. Their small size and remarkable stability make them exciting molecules for protein engineering to achieve superior selectivity and efficacy. In this report, we have designed a set of AAI pro- and mature peptides chimeras. Based on in silico analysis, stable AAI chimeras having a stronger affinity with target amylases were selected for characterization. In vitro studies validated that chimera of the propeptide from Chenopodium quinoa a-AI and mature peptide from Beta vulgaris a-AI possess 3, 7.6, and 4.26 fold higher inhibition potential than parental counterparts. Importantly, recombinant AAI chimera retained specificity towards target coleopteran a-amylases. In addition, to improve the inhibitory potential of AAI, we performed in silico site-saturation mutagenesis. Computational analysis followed by experimental data showed that substituting Asparagine at the 6th position with Methionine had a remarkable increase in the specific inhibition potential of Amaranthus hypochondriacus a-AI. These results provide structural-functional insights into the vitality of AAI propeptide and a potential hotspot for mutagenesis to enhance the AAI activity. Our investigation will be a toolkit for AAI{\textquoteright}s optimization and functional differentiation for future biotechnological applications.

}, keywords = {\& alpha, -Amylase, -Amylase inhibitors, Amaranthaceae, Coleoptera, Peptide, Pest control}, issn = {1572-3887}, doi = {10.1007/s10930-023-10148-y}, author = {Rane, Ashwini S. and Nair, Vineetkumar S. and Joshi, Rakesh S. and Giri, Ashok P.} }