03017nas a2200277 4500008004100000022001400041245013800055210006900193260007700262300001400339490000700353520197800360653001002338653003002348653003402378653001102412653002102423653002902444100001902473700002802492700002102520700002502541700002102566700002002587856013202607 2010 eng d a1615-985300aInteraction of recombinant CanPIs with helicoverpa armigera gut proteases reveals their processing patterns, stability and efficiency0 aInteraction of recombinant CanPIs with helicoverpa armigera gut  aPO BOX 10 11 61, D-69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJUL a2845-28570 v103 a

Six diverse representative Capsicum annuum (common name: hot pepper; Solanaceae) protease inhibitor genes, viz CanPI-5, -7, -13, -15, -19, and 22 comprising 1-4 inhibitory repeat domains (IRDs), were cloned and expressed in Pichia pastoris. The recombinant proteins were evaluated for their interactions with bovine trypsin, chymotrypsin, and Helicoverpa armigera gut proteases (HGP) using electrophoretic (native and denaturing) and mass spectrometric (MALDI-TOF-MS in combination with intensity fading assays) techniques. These techniques allow qualitative and semiquantitative analysis of multiple and processed IRDs of purified recombinant Capsicum annuum proteinase inhibitor (rCanPI) proteins. rCanPIs showed over 90% trypsin inhibition, varying chymotrypsin inhibition depending on the number of respective IRDs and over 60% inhibition of total HGP. rCanPI-15 that has only one IRD showed exceptionally low inhibition of these proteases. Interaction studies of rCanPIs with proteases using intensity fading-MALDI-TOF-MS revealed gradual processing of multi-IRD rCanPIs into single IRD forms by the action of HGP at the linker region, unlike their interactions with trypsin and chymotrypsin. Intensity fading-MALDI-TOF-MS assay showed that CanPI-13 and -15, possessing single IRD and expressed predominantly in stem tissue are degraded by HGP; indicating their function other than defense. In vitro and in vivo studies on rCanPI-5 and -7 showed maximum inhibition of HGP isoforms and their processed IRDs were also found to be stable in the presence of HGP. Even single amino acid variations in IRDs were found to change the HGP specificity like in the case of HGP-8 inhibited only by IRD-12. The presence of active PI in insect gut might be responsible for changed HGP profile. rCanPI-5 and -7 enhanced HGP-7, reduced HGP-4, -5, -10 expression and new protease isoforms were induced. These results signify isoform complexity in plant PIs and insect proteases.

10aCanPI10aH. armigera gut proteases10aIntensity fading MALDI-TOF-MS10aPin-II10aPlant proteomics10aPlant-insect interaction1 aMishra, Manasi1 aTamhane, Vaijayanti, A.1 aKhandelwal, Neha1 aKulkarni, Mahesh, J.1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/interaction-recombinant-canpis-helicoverpa-armigera-gut-proteases-reveals-their-processing-003296nas a2200277 4500008004100000022001400041245007100055210006900126260008100195300000800276490000700284520235500291653001002646653001402656653002002670653003802690653002902728100001902757700002202776700002802798700002502826700002102851700002102872700002002893856010502913 2012 eng d a1471-222900aStress inducible proteinase inhibitor diversity in capsicum annuum0 aStress inducible proteinase inhibitor diversity in capsicum annu a236 GRAYS INN RD, FLOOR 6, LONDON WC1X 8HL, ENGLANDbBIOMED CENTRAL LTDcNOV a2170 v123 a

Background: Wound-inducible Pin-II Proteinase inhibitors (PIs) are one of the important plant serine PIs which have been studied extensively for their structural and functional diversity and relevance in plant defense against insect pests. To explore the functional specialization of an array of Capsicum annuum (L.) proteinase inhibitor (CanPIs) genes, we studied their expression, processing and tissue-specific distribution under steady-state and induced conditions. Inductions were performed by subjecting C. annuum leaves to various treatments, namely aphid infestation or mechanical wounding followed by treatment with either oral secretion (OS) of Helicoverpa armigera or water. Results: The elicitation treatments regulated the accumulation of CanPIs corresponding to 4-, 3-, and 2-inhibitory repeat domains (IRDs). Fourty seven different CanPI genes composed of 28 unique IRDs were identified in total along with those reported earlier. The CanPI gene pool either from uninduced or induced leaves was dominated by 3-IRD PIs and trypsin inhibitory domains. Also a major contribution by 4-IRD CanPI genes possessing trypsin and chymotrypsin inhibitor domains was specifically revealed in wounded leaves treated with OS. Wounding displayed the highest number of unique CanPIs while wounding with OS treatment resulted in the high accumulation of specifically CanPI-4, -7 and -10. Characterization of the PI protein activity through two dimensional gel electrophoresis revealed tissue and induction specific patterns. Consistent with transcript abundance, wound plus OS or water treated C. annuum leaves exhibited significantly higher PI activity and isoform diversity contributed by 3- and 4-IRD CanPIs. CanPI accumulation and activity was weakly elicited by aphid infestation yet resulted in the higher expression of CanPI-26, -41 and -43. Conclusions: Plants can differentially perceive various kinds of insect attacks and respond appropriately through activating plant defenses including regulation of PIs at transcriptional and post-translational levels. Based on the differentially elicited CanPI accumulation patterns, it is intriguing to speculate that generating sequence diversity in the form of multi-IRD PIs is a part of elaborative plant defense strategy to obtain a diverse pool of functional units to confine insect attack.

10aCanPI10aHerbivory10aOral secretions10aPin-II type proteinase inhibitors10aPlant-insect interaction1 aMishra, Manasi1 aMahajan, Neha, S.1 aTamhane, Vaijayanti, A.1 aKulkarni, Mahesh, J.1 aBaldwin, Ian, T.1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/stress-inducible-proteinase-inhibitor-diversity-capsicum-annuum-002516nas a2200265 4500008004100000022001400041245012500055210006900180260007300249300001400322490000900336520153000345653001901875653002101894653003601915653001301951653002301964653003201987100002202019700001902041700001902060700002102079700002002100856013002120 2013 eng d a0304-416500aComplementation of intramolecular interactions for structural-functional stability of plant serine proteinase inhibitors0 aComplementation of intramolecular interactions for structuralfun aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcNOV a5087-50940 v18303 a

Background: Plant protease inhibitors (PIs) constitute a diverse group of proteins capable of inhibiting proteases. Among Pls, serine Pls (SPIs) display stability and conformational restrictions of the reactive site loop by virtue of their compact size, and by the presence of disulfide bonds, hydrogen bonds, and other weak interactions. Scope of review: The significance of various intramolecular interactions contributing to protein folding mechanism and their role in overall stability and activity of SPIs is discussed here. Furthermore, we have reviewed the effect of variation or manipulation of these interactions on the activity/stability of SPIs. Major conclusions: The selective gain or loss of disulfide bond(s) in SPIs can be associated with their functional differentiation, which is likely to be compensated by non-covalent interactions (hydrogen bonding or electrostatic interactions). Thus, these intramolecular interactions are collectively responsible for the functional activity of SPIs, through the maintenance of scaffold framework, conformational rigidity and shape complementarities of reactive site loop. General significance: Structural insight of these interactions will provide an in-depth understanding of kinetic and thermodynamic parameters involved in the folding and stability mechanisms of SPIs. These features can be explored for engineering canonical SPIs for optimizing their overall stability and functionality for various applications. (C) 2013 Elsevier B.V. All rights reserved.

10aDisulfide bond10ahydrogen bonding10aIntramolecular weak interaction10aProtease10aReactive site loop10aSerine proteinase inhibitor1 aJoshi, Rakesh, S.1 aMishra, Manasi1 aSuresh, C., G.1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/complementation-intramolecular-interactions-structural-functional-stability-plant-serine-002194nas a2200181 4500008004100000245013200041210006900173260000800242300001600250490000900266520149500275100002201770700001901792700002801811700002101839700002001860856013201880 2013 eng d00aPlasticity of protease gene expression in helicoverpa armigera upon exposure to multi-domain capsicum annuum protease inhibitor0 aPlasticity of protease gene expression in helicoverpa armigera u cMAR a3414–34200 v18303 a

Background A multi-domain Pin-II type protease inhibitor from Capsicum annuum (CanPI-7) is known to be effective against the insect pest, Helicoverpa armigera. The present study is an attempt to investigate the optimal dose of recombinant CanPI-7 (rCanPI-7) for effective antibiosis to H. armigera and further to characterize the responses of digestive proteases upon rCanPI-7 ingestion. Methods The gut protease activity was assessed biochemically and transcript accumulation pattern for selected trypsin and chymotrypsin genes was analyzed by quantitative Real-Time PCR. Results The growth retardation upon exposure to rCanPI-7 was more prominent in neonates as compared to third instar larvae. Influence of stage and dosage of rCanPI-7 was conspicuous on the expression and regulation of candidate trypsin and chymotrypsin genes in H. armigera. The transcript accumulation pattern correlated with the protease activity in rCanPI-7 exposed larvae. Conclusions We conclude that early exposure and specific dose of protease inhibitor are essential for effective antibiosis despite the large diversity and plasticity in the expression of protease genes in H. armigera. Moreover, it is also evident that the regulation and expression of H. armigera gut proteases are specific to the stage of PI exposure. General significance These results highlight the requirement of optimal PI concentration for effective growth retardation and for inhibiting the major gut proteases of H. armigera.

1 aMahajan, Neha, S.1 aMishra, Manasi1 aTamhane, Vaijayanti, A.1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/plasticity-protease-gene-expression-helicoverpa-armigera-upon-exposure-multi-domain-capsicum02054nas a2200253 4500008004100000022001400041245009800055210006900153260009500222300001400317490000800331520110600339653001001445653002301455653002201478653003901500653002201539100001901561700002201580700002501602700002101627700002001648856013201668 2013 eng d a0006-291X00aStructural-functional insights of single and multi-domain capsicum annuum protease inhibitors0 aStructuralfunctional insights of single and multidomain capsicum a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcJAN a1060-10650 v4303 a

Pin-II protease inhibitors (PIs) are the focus of research interest because of their large structural-functional diversity and relevance in plant defense. Two representative Capsicum annuum PI genes (CanPI-15 and -7) comprising one and four inhibitory repeat domains, respectively, were expressed and recombinant proteins were characterized. beta-Sheet and unordered structure was found predominant in CanPI-15 while -7 also displayed the signatures of polyproline fold, as revealed by circular dichroism studies. Inhibition kinetics against bovine typsin indicated three times higher potency of CanPI-7 (K-i similar to 57 mu M) than -15 (similar to 184 mu M). Activity and structural stability of these CanPIs were revealed under various conditions of pH, temperature and denaturing agent. Structure prediction, docking studies with proteases and mass spectroscopy revealed the organization of multiple reactive site loops of multi domain PIs in space as well as the steric hindrances imposed while binding to proteases due to their close proximity. (C) 2012 Elsevier Inc. All rights reserved.

10aCanPI10aCircular dichroism10aDisulfide bonding10aPotato type-II protease inhibitors10aProtein stability1 aMishra, Manasi1 aJoshi, Rakesh, S.1 aGaikwad, Sushama, M.1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/structural-functional-insights-single-and-multi-domain-capsicum-annuum-protease-inhibitors-002993nas a2200289 4500008004100000022001400041245017700055210006900232260008600301300001000387490000700397520189300404653002002297653002502317653001402342653002502356100002202381700001902403700002802422700001902450700002402469700001902493700002002512700002102532700002002553856013002573 2014 eng d a0739-110200aRemarkable efficiency of a pin-II proteinase inhibitor sans two conserved disulfide bonds is due to enhanced flexibility and hydrogen bond density in the reactive site loop0 aRemarkable efficiency of a pinII proteinase inhibitor sans two c a325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USAbTAYLOR & FRANCIS INCcJAN a13-260 v323 a

Capsicum annuum (L.) expresses diverse potato type II family proteinase inhibitors comprising of inhibitory repeat domain (IRD) as basic functional unit. Most IRDs contain eight conserved cysteines forming four disulfide bonds, which are indispensible for their stability and activity. We investigated the functional significance of evolutionary variations in IRDs and their role in mediating interaction between the inhibitor and cognate proteinase. Among the 18 IRDs encoded by C. annuum, IRD-7, -9, and -12 were selected for further characterization on the basis of variation in their reactive site loop, number of conserved cysteine residues, and higher theoretical G(bind) for interaction with Helicoverpa armigera trypsin. Moreover, inhibition kinetics showed that IRD-9, despite loss of some of the disulfide bonds, was a more potent proteinase inhibitor among the three selected IRDs. Molecular dynamic simulations revealed that serine residues in the place of cysteines at seventh and eighth positions of IRD-9 resulted in an increase in the density of intramolecular hydrogen bonds and reactive site loop flexibility. Results of the serine residues chemical modification also supported this observation and provided a possible explanation for the remarkable inhibitory potential of IRD-9. Furthermore, this natural variant among IRDs showed special attributes like stability to proteolysis and synergistic inhibitory effect on other IRDs. It is likely that IRDs have coevolved selective specialization of their structure and function as a response towards specific insect proteases they encountered. Understanding the molecular mechanism of pest protease-plant proteinaceous inhibitor interaction will help in developing effective pest control strategies.An animated interactive 3D complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:39

10aCapsicum annuum10aHelicoverpa armigera10aProteases10aProteinase inhibitor1 aJoshi, Rakesh, S.1 aMishra, Manasi1 aTamhane, Vaijayanti, A.1 aGhosh, Anirban1 aSonavane, Uddhavesh1 aSuresh, C., G.1 aJoshi, Rajendra1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/remarkable-efficiency-pin-ii-proteinase-inhibitor-sans-two-conserved-disulfide-bonds-due-002056nas a2200229 4500008004100000022001400041245006500055210006500120260010300185300001200288490000700300520125600307653002001563653002101583653001301604100002201617700001901639700002801658700002101686700002001707856009901727 2014 eng d a0981-942800aStress inducible proteomic changes in capsicum annuum leaves0 aStress inducible proteomic changes in capsicum annuum leaves a23 RUE LINOIS, 75724 PARIS, FRANCEbELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIERcJAN a212-2170 v743 a

Herbivore attack induces defense responses in plants, activating several signaling cascades. As a result, molecules deterrent to the herbivores are produced and accumulated in plants. Expression of defense mechanism/traits requires reorganization of the plant metabolism, redirecting the resources otherwise meant for growth. In the present work, protein profile of Capsicum annuum leaves was examined after herbivore attack/induction. Majority of proteins identified as differentially accumulated, were having roles in redox metabolism and photosynthesis. For example, superoxide dismutase and NADP oxidoreductase were upregulated by 10- and 6-fold while carbonic anhydrase and fructose-1,6-bisphosphatase were downregulated by 9- and 4-fold, respectively. Also, superoxide dismutase, NADPH quinone oxidoreductase and NADP dependent isocitrate dehydrogenase transcripts showed a higher accumulation in induced leaf tissues at early time points. In general, proteins having role in defense and damage repair were upregulated while those involved in photosynthesis appeared downregulated. Thus metabolic reconfiguration to balance defense and tolerance was evident in the stress-induced leaves. (C) 2013 Elsevier Masson SAS. All rights reserved.

10aCapsicum annuum10aOxidative stress10aWounding1 aMahajan, Neha, S.1 aMishra, Manasi1 aTamhane, Vaijayanti, A.1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/stress-inducible-proteomic-changes-capsicum-annuum-leaves-003064nas a2200265 4500008004100000022001400041245009700055210006900152260005700221300001200278490000800290520213900298653002002437653001702457653001402474653002302488653002902511100001902540700002802559700002202587700002402609700002102633700002002654856012402674 2015 eng d a0032-093500aEcological turmoil in evolutionary dynamics of plant-insect interactions: defense to offence0 aEcological turmoil in evolutionary dynamics of plantinsect inter a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcOCT a761-7710 v2423 a

Available history manifests contemporary diversity that exists in plant-insect interactions. A radical thinking is necessary for developing strategies that can co-opt natural insect-plant mutualism, ecology and environmental safety for crop protection since current agricultural practices can reduce species richness and evenness. The global environmental changes, such as increased temperature, CO (2) and ozone levels, biological invasions, land-use change and habitat fragmentation together play a significant role in re-shaping the plant-insect multi-trophic interactions. Diverse natural products need to be studied and explored for their biological functions as insect pest control agents. In order to assure the success of an integrated pest management strategy, human activities need to be harmonized to minimize the global climate changes. Plant-insect interaction is one of the most primitive and co-evolved associations, often influenced by surrounding changes. In this review, we account the persistence and evolution of plant-insect interactions, with particular focus on the effect of climate change and human interference on these interactions. Plants and insects have been maintaining their existence through a mutual service-resource relationship while defending themselves. We provide a comprehensive catalog of various defense strategies employed by the plants and/or insects. Furthermore, several important factors such as accelerated diversification, imbalance in the mutualism, and chemical arms race between plants and insects as indirect consequences of human practices are highlighted. Inappropriate implementation of several modern agricultural practices has resulted in (i) endangered mutualisms, (ii) pest status and resistance in insects and (iii) ecological instability. Moreover, altered environmental conditions eventually triggered the resetting of plant-insect interactions. Hence, multitrophic approaches that can harmonize human activities and minimize their interference in native plant-insect interactions are needed to maintain natural balance between the existence of plants and insects.

10aClimatic change10aCo-evolution10aEcosystem10aHuman interference10aPlant-insect interaction1 aMishra, Manasi1 aLomate, Purushottam, R.1 aJoshi, Rakesh, S.1 aPunekar, Sachin, A.1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/ecological-turmoil-evolutionary-dynamics-plant-insect-interactions-defense-offence-002856nas a2200277 4500008004100000022001400041245009000055210006900145260005700214300001200271490000800283520193300291653001002224653001302234653002202247653001302269653002502282100002202307700002002329700002802349700002202377700001902399700002102418700002002439856011902459 2015 eng d a0032-093500aStructural features of diverse Pin-II proteinase inhibitor genes from capsicum annuum0 aStructural features of diverse PinII proteinase inhibitor genes  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcFEB a319-3310 v2413 a

The proteinase inhibitor (PI) genes from Capsicum annuum were characterized with respect to their UTR, introns and promoter elements. The occurrence of PIs with circularly permuted domain organization was evident. Several potato inhibitor II (Pin-II) type proteinase inhibitor (PI) genes have been analyzed from Capsicum annuum (L.) with respect to their differential expression during plant defense response. However, complete gene characterization of any of these C. annuum PIs (CanPIs) has not been carried out so far. Complete gene architectures of a previously identified CanPI-7 (Beads-on-string, Type A) and a member of newly isolated Bracelet type B, CanPI-69 are reported in this study. The 5' UTR (untranslated region), 3'UTR, and intronic sequences of both the CanPI genes were obtained. The genomic sequence of CanPI-7 exhibited, exon 1 (49 base pair, bp) and exon 2 (740 bp) interrupted by a 294-bp long type I intron. We noted the occurrence of three multi-domain PIs (CanPI-69, 70, 71) with circularly permuted domain organization. CanPI-69 was found to possess exon 1 (49 bp), exon 2 (551 bp) and a 584-bp long type I intron. The upstream sequence analysis of CanPI-7 and CanPI-69 predicted various transcription factor-binding sites including TATA and CAAT boxes, hormone-responsive elements (ABRELATERD1, DOFCOREZM, ERELEE4), and a defense-responsive element (WRKY71OS). Binding of transcription factors such as zinc finger motif MADS-box and MYB to the promoter regions was confirmed using electrophoretic mobility shift assay followed by mass spectrometric identification. The 3' UTR analysis for 25 CanPI genes revealed unique/distinct 3' UTR sequence for each gene. Structures of three domain CanPIs of type A and B were predicted and further analyzed for their attributes. This investigation of CanPI gene architecture will enable the better understanding of the genetic elements present in CanPIs.

10aCanPI10aCapsicum10aGene architecture10aPromoter10aProteinase inhibitor1 aMahajan, Neha, S.1 aDewangan, Veena1 aLomate, Purushottam, R.1 aJoshi, Rakesh, S.1 aMishra, Manasi1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/structural-features-diverse-pin-ii-proteinase-inhibitor-genes-capsicum-annuum-002420nas a2200265 4500008004100000245011300041210006900154260000800223300000600231490000700237520156200244653001401806653003101820653001401851653001301865653001301878653001101891653002401902100001901926700001901945700002601964700002201990700001902012856012302031 2021 eng d00aRepurposing the McoTI-II rigid molecular scaffold in to inhibitor of `papain superfamily' cysteine proteases0 aRepurposing the McoTIII rigid molecular scaffold in to inhibitor cJAN a70 v143 a

Clan C1A or `papain superfamily' cysteine proteases are key players in many important physiological processes and diseases in most living systems. Novel approaches towards the development of their inhibitors can open new avenues in translational medicine. Here, we report a novel design of a re-engineered chimera inhibitor Mco-cysteine protease inhibitor (CPI) to inhibit the activity of C1A cysteine proteases. This was accomplished by grafting the cystatin first hairpin loop conserved motif (QVVAG) onto loop 1 of the ultrastable cyclic peptide scaffold McoTI-II. The recombinantly expressed Mco-CPI protein was able to bind with micromolar affinity to papain and showed remarkable thermostability owing to the formation of multi-disulphide bonds. Using an in silico approach based on homology modelling, protein-protein docking, the calculation of the free-energy of binding, the mechanism of inhibition of Mco-CPI against representative C1A cysteine proteases (papain and cathepsin L) was validated. Furthermore, molecular dynamics simulation of the Mco-CPI-papain complex validated the interaction as stable. To conclude, in this McoTI-II analogue, the specificity had been successfully redirected towards C1A cysteine proteases while retaining the moderate affinity. The outcomes of this study pave the way for further modifications of the Mco-CPI design for realizing its full potential in therapeutics. This study also demonstrates the relevance of ultrastable peptide-based scaffolds for the development of novel inhibitors via grafting.

10aCathepsin10aClan CA cysteine proteases10acyclotide10acystatin10aMcoTI-II10apapain10aprotein engineering1 aMishra, Manasi1 aSingh, Vigyasa1 aTellis, Meenakshi, B.1 aJoshi, Rakesh, S.1 aSingh, Shailja uhttps://library.ncl.res.in/content/repurposing-mcoti-ii-rigid-molecular-scaffold-inhibitor-papain-superfamily-cysteine02369nas a2200289 4500008004100000022001400041245013700055210006900192260000800261300001400269490000700283520140400290653001901694653002501713653001501738653000601753653001801759653003101777653001901808100001901827700001901846700002601865700002201891700002401913700001901937856012301956 2022 eng d a0739-110200aCyclic peptide engineered from phytocystatin inhibitory hairpin loop as an effective modulator of falcipains and potent antimalarial0 aCyclic peptide engineered from phytocystatin inhibitory hairpin  cMAY a3642-36540 v403 a

Cystatins are classical competitive inhibitors of C1 family cysteine proteases (papain family). Phytocystatin superfamily shares high sequence homology and typical tertiary structure with conserved glutamine-valine-glycine (Q-X-V-X-G) loop blocking the active site of C1 proteases. Here, we develop a cysteine-bounded cyclic peptide (CYS-cIHL) and linear peptide (CYS-IHL), using the conserved inhibitory hairpin loop amino acid sequence. Using an in silico approach based on modeling, protein-peptide docking, molecular dynamics simulations and calculation of free energy of binding, we designed and validated inhibitory peptides against falcipain-2 (FP-2) and -3 (FP-3), cysteine proteases from the malarial parasite Plasmodium falciparum. Falcipains are critical hemoglobinases of P. falciparum that are validated targets for the development of antimalarial therapies. CYS-cIHL was able to bind with micromolar affinity to FP-2 and modulate its binding with its substrate, hemoglobin in in vitro and in vivo assays. CYS-cIHL could effectively block parasite growth and displayed antimalarial activity in culture assays with no cytotoxicity towards human cells. These results indicated that cyclization can substantially increase the peptide affinity to the target. Furthermore, this can be applied as an effective strategy for engineering peptide inhibitory potency against proteases.

10aCyclic peptide10afalcipain inhibitors10afalciparum10aP10aPhytocystatin10aprotein interaction mimics10aprotein&\#82111 aMishra, Manasi1 aSingh, Vigyasa1 aTellis, Meenakshi, B.1 aJoshi, Rakesh, S.1 aPandey, Kailash, C.1 aSingh, Shailja uhttps://library.ncl.res.in/content/cyclic-peptide-engineered-phytocystatin-inhibitory-hairpin-loop-effective-modulator