Molecular cloning,expression, and cytokinin (6-benzylaminopurine) antagonist activity of peanut (Arachis hypogaea) lectin SL-I |
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Authors: | Monika?Pathak,Bharat?Singh,Amit?Sharma,Praveen?Agrawal,Santosh?B.?Pasha,Hasi?R.?Das,Rakha?H.?Das author-information" > author-information__contact u-icon-before" > mailto:rakhahdas@yahoo.com" title=" rakhahdas@yahoo.com" itemprop=" email" data-track=" click" data-track-action=" Email author" data-track-label=" " >Email author |
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Affiliation: | (1) Unit of Proteomics and Comparative Genomics, Institute of Genomics and Integrative Biology, Delhi University Campus, Mall Road, Delhi, 110 007, India |
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Abstract: | Isolation and purification of a α-methyl-mannoside specific lectin (SL-I) of peanut was reported earlier [Singh and Das (1994) Glycoconj J 11:282–285]. Native SL-I is a glycoprotein having ∼31 kDa subunit molecular mass and forms dimer. The gene encoding this lectin is identified from a 6-day old peanut root cDNA library by anti-SL-I antibody and N-terminal amino acid sequence homology to the native lectin. Nucleotide sequence derived amino acid sequence of the re-SL-I shows amino acid sequence homology with the N-terminal and tryptic digests’ amino acid sequence of the native SL-I (nSL-I). Presence of a putative glycosylation (QNPS) site and a hydrophobic adenine-binding (VLVSYDANS) site is also identified in SL-I. Homology modeling of the lectin suggests it to be an archetype of legume lectins. It is expressed as a ~30 kDa apoprotein in E. coli and has the carbohydrate specificity and secondary structure identical to its natural counterpart. The lectin SL-I inhibits cytokinin 6-benzylaminopurine (BA)-induced “delayed leaf senescence” and “cotyledon expansion”. Equilibrium dialysis revealed a single high-affinity binding site for adenine (7.6 × 10−6 M) and BA (1.09 × 10−5 M) in the SL-I dimer and thus suggesting that the cytokinin antagonist effect of SL-I is mediated by the direct interaction of SL-I with BA.The nucleotide sequence data reported here are available in the DDBJ/EMBL/GenBank databases under the Accession No. AJ585523 |
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Keywords: | Peanut lectin SL-I Gene expression Cytokinin 6-benzylaminopurine Cytokinin antagonist activity |
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