02696nas a2200301   4500008004100000022001400041245016000055210006900215260010600284300000900390490000700399520155800406653001301964653001801977653002801995653002902023653001502052653002402067100002402091700002002115700001902135700002002154700002202174700002302196700002602219700002002245856012902265       2016                        eng d  a0965-174800aCharacterization of two coleopteran alpha-amylases and molecular insights into their differential inhibition by synthetic alpha-amylase inhibitor, acarbose0 aCharacterization of two coleopteran alphaamylases and molecular   aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUL  a1-110 v743 a<p>Post-harvest insect infestation of stored grains makes them unfit for human consumption and leads to severe economic loss. Here, we report functional and structural characterization of two coleopteran alpha-amylases viz. Callosobruchus chinensis alpha-amylase (CcAmy) and Tribolium castaneum alpha-amylase (TcAmy) along with their interactions with proteinaceous and non-proteinaceous alpha-amylase inhibitors. Secondary structural alignment of CcAmy and TcAmy with other coleopteran alpha-amylases revealed conserved motifs, active sites, di-sulfide bonds and two point mutations at spatially conserved substrate or inhibitor binding sites. Homology modeling and molecular docking showed structural differences between these two enzymes. Both the enzymes had similar optimum pH values but differed in their optimum temperature. Overall, pattern of enzyme stabilities were similar under various temperature and pH conditions. Further, CcAmy and TcAmy differed in their substrate affinity and catalytic efficiency towards starch and amylopectin. HPLC analysis detected common amylolytic products like maltose and maltotriose while glucose and malto-tetrose were unique in CcAmy and TcAmy catalyzed reactions respectively. At very low concentrations, wheat alpha-amylase inhibitor was found to be superior over the acarbose as far as complete inhibition of amylolytic activities of CcAmy and TcAmy was concerned. Mechanism underlying differential amylolytic reaction inhibition by acarbose was discussed. (C) 2016 Elsevier Ltd. All rights reserved.</p>10aAcarbose10aalpha-amylase10aalpha-amylase inhibitor10aCallosobruchus chinensis10aColeoptera10aTribolium castaneum1 aChannale, Sonal, M.1 aBhide, Amey, J.1 aYadav, Yashpal1 aKashyap, Garima1 aPawar, Pankaj, K.1 aMaheshwari, V., L.1 aRamasamy, Sureshkumar1 aGiri, Ashok, P.  uhttps://library.ncl.res.in/content/characterization-two-coleopteran-alpha-amylases-and-molecular-insights-their-differential02489nas a2200241   4500008004100000022001400041245010400055210006900159260000800228300001400236490000800250520167700258653001801935653002801953653001801981653001501999653001702014100002202031700002102053700002202074700002002096856013102116       2020                        eng d  a0141-813000aMolecular investigation of coleopteran specific alpha-amylase inhibitors from amaranthaceae members0 aMolecular investigation of coleopteran specific alphaamylase inh  cNOV  a1444-14500 v1633 a<p>alpha-Amylase inhibitors (alpha-AIs) target alpha-amylases and interfere with the carbohydrate digestion of insects. Among different classes of alpha-AIs, a knottin-type inhibitor from Amaranthus hypochondriacus (AhAI) was found to be specific against coleopteran storage pests. In this report, we have characterized three previously unidentified knottin-type alpha-AIs from various Amaranthaceae plants namely, Amaranthus hypochondriacus (AhAI2), Alternanthera sessilis (AsAI) and Chenopodium quinoa (CqAI). They contain a signal peptide, pro-peptide, and mature peptide. The mature peptides of the new alpha-AIs shared 68 to 78% identity with AhAI and have highly variable pro-peptide regions. Along with the cystine-knot fold, they showed conservation of reactive site residues. All recombinant alpha-AIs were successfully expressed in their active form and native state using an oxidative cytoplasmic environment. Inhibition studies against various amylases revealed that these inhibitors showed selective inhibition of coleopteran recombinant insect alpha-amylases viz., Tribolium castaneum, and Callosobruchus chinensis. Tribolium castaneum alpha-amylase inhibition potency was highest for AhAI2 (Ki similar to 15 mu M) followed by AsAI (Ki similar to 43 mu M) and CqAI (Ki similar to 61 mu M). Interaction analysis of these inhibitors illustrated that the reactive site of inhibitors make several non-covalent interactions with the substrate-binding pocket of coleopteran alpha-amylases. The selectivity of these inhibitors against coleopteran a-amylases highlights their potential in storage grain pest control. (C) 2020 Elsevier B.V. All rights reserved.</p>
10aalpha-amylase10aalpha-amylase inhibitor10aAmaranthaceae10aColeoptera10aKnottin-type1 aRane, Ashwini, S.1 aVenkatesh, Varun1 aJoshi, Rakesh, S.1 aGiri, Ashok, P.  uhttps://library.ncl.res.in/content/molecular-investigation-coleopteran-specific-alpha-amylase-inhibitors-amaranthaceae-members02323nas a2200265   4500008004100000022001400041245013000055210006900185260000800254300001200262490000700274520144300281653001201724653001301736653002401749653001801773653001501791653001201806653001701818100002201835700002601857700002201883700002001905856013201925       2023                        eng d  a1572-388700aDomain shuffling and site-saturation mutagenesis for the enhanced inhibitory potential of amaranthaceae α-amylase inhibitors0 aDomain shuffling and sitesaturation mutagenesis for the enhanced  cOCT  a519-5320 v423 a<p>
	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's optimization and functional differentiation for future biotechnological applications.</p>
10a& alpha10a-Amylase10a-Amylase inhibitors10aAmaranthaceae10aColeoptera10aPeptide10aPest control1 aRane, Ashwini, S.1 aNair, Vineetkumar, S.1 aJoshi, Rakesh, S.1 aGiri, Ashok, P.  uhttps://library.ncl.res.in/content/domain-shuffling-and-site-saturation-mutagenesis-enhanced-inhibitory-potential-amaranthaceae