<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Katre, Uma V.</style></author><author><style face="normal" font="default" size="100%">Suresh, C. G.</style></author><author><style face="normal" font="default" size="100%">Khan, Mohammad Islam</style></author><author><style face="normal" font="default" size="100%">Gaikwad, Sushama M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Steady state and time-resolved fluorescence studies of a hemagglutinin from Moringa oleifera</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Fluorescence</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">ANS binding</style></keyword><keyword><style  face="normal" font="default" size="100%">fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">Hemagglutinin</style></keyword><keyword><style  face="normal" font="default" size="100%">lifetime</style></keyword><keyword><style  face="normal" font="default" size="100%">Moringa oleifera</style></keyword><keyword><style  face="normal" font="default" size="100%">saccharide binding</style></keyword><keyword><style  face="normal" font="default" size="100%">Solute quenching</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">MAR</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">2</style></number><publisher><style face="normal" font="default" size="100%">SPRINGER/PLENUM PUBLISHERS</style></publisher><pub-location><style face="normal" font="default" size="100%">233 SPRING ST, NEW YORK, NY 10013 USA</style></pub-location><volume><style face="normal" font="default" size="100%">18</style></volume><pages><style face="normal" font="default" size="100%">479-485</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The saccharide binding and conformational characterization of a hemagglutinin, a low molecular weight protein from the seeds of Moringa oleifera was studied using steady state and time resolved fluorescence. The lectin binds sugars LacNAc (K-a = 1380 M-1) and fructose (K-a = 975 M-1), as determined by the fluorescence spectroscopy. It has a single tryptophan per monomer which is exposed on the surface and is in a strong electropositive environment as revealed by quenching with iodide. Quenching of the fluorescence by acrylamide involved both static (K-s = 0.216 M-1) and collisional (K-sv= 8.19 M-1) components. The native protein showed two different lifetimes, tau(1) (1.6 ns) and tau(2) (4.36 ns) which decrease and get converted into a single one, (2.21 ns) after quenching with 0.15 M acrylamide. The bimolecular quenching constant, k(q) was 7.55 x 10(11) M-1 s(-1). ANS binding studies showed that the native protein has exposed hydrophobic patches which get further exposed at extreme acidic or alkaline pH. However, they get buried in the interior of the protein in presence of 1 M GdnHCl or urea.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">1.966</style></custom4></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Dharker, Poorva N.</style></author><author><style face="normal" font="default" size="100%">Gaikwad, Sushama M.</style></author><author><style face="normal" font="default" size="100%">Suresh, C. G.</style></author><author><style face="normal" font="default" size="100%">Dhuna, Vikram</style></author><author><style face="normal" font="default" size="100%">Khan, Mohammad Islam</style></author><author><style face="normal" font="default" size="100%">Singh, Jatinder</style></author><author><style face="normal" font="default" size="100%">Kamboj, Sukhdev Singh</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Comparative studies of two araceous lectins by steady state and time-resolved fluorescence and CD spectroscopy</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Fluorescence</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Araceae lectins</style></keyword><keyword><style  face="normal" font="default" size="100%">Denaturation</style></keyword><keyword><style  face="normal" font="default" size="100%">fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">Lifetime spectroscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">Secondary structure</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">MAR</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">2</style></number><publisher><style face="normal" font="default" size="100%">SPRINGER/PLENUM PUBLISHERS</style></publisher><pub-location><style face="normal" font="default" size="100%">233 SPRING ST, NEW YORK, NY 10013 USA</style></pub-location><volume><style face="normal" font="default" size="100%">19</style></volume><pages><style face="normal" font="default" size="100%">239-248</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Transitions in the tryptophan microenvironment and secondary structure of two monocot lectins from Sauromatum guttatum and Arisaema tortuosum under different denaturing conditions were studied by steady state and time resolved fluorescence and CD spectroscopy. The lectins exist as tetramers with a single tryptophan residue estimated per monomer, present in a polar environment. Quenching with ionic quenchers showed predominantly electropositive environment for tryptophan residues. Acrylamide had maximum quenching effect. A decrease in KI quenching due to lectin denaturation indicated redistribution of charges as a result of possible conformational change. The two values for lifetimes of tryptophanyl population (1.2-1.4 and 6.3-6.4 ns) reduced substantially on quenching or denaturation. Similarly, both the lectins showed a drastic loss of secondary structure in 5 M Gdn-HCl or 6 M Urea or at pH 2.0 and below. For the first time araceous lectins, like legume lectins are shown to bind adenine. The presence of a compact structure at alkaline pH 10.0-12.0 was observed in CD spectra.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">1.966</style></custom4></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Khan, Feroz</style></author><author><style face="normal" font="default" size="100%">Ahmad, Absar</style></author><author><style face="normal" font="default" size="100%">Khan, Mohammad Islam</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Steady state and time resolved fluorescence quenching and chemical modification studies of a lectin from endophytic fungus fusarium solani</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Fluorescence</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Chemical modification</style></keyword><keyword><style  face="normal" font="default" size="100%">fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">Fusarium</style></keyword><keyword><style  face="normal" font="default" size="100%">Lectin</style></keyword><keyword><style  face="normal" font="default" size="100%">Quenching</style></keyword><keyword><style  face="normal" font="default" size="100%">Time-resolved</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">JAN</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">1</style></number><publisher><style face="normal" font="default" size="100%">SPRINGER/PLENUM PUBLISHERS</style></publisher><pub-location><style face="normal" font="default" size="100%">233 SPRING ST, NEW YORK, NY 10013 USA</style></pub-location><volume><style face="normal" font="default" size="100%">20</style></volume><pages><style face="normal" font="default" size="100%">305-313</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The solute quenching studies of a lectin from endophytic fungus Fusarium solani were carried out using different quenchers such as acrylamide, succinimide, potassium iodide and cesium chloride. The lectin showed emission maximum at 348 nm indicating relative exposure of tryptophan. The quenchable fraction of the fluorophore was 100% with acrylamide, whereas it was only 50% with succinimide. The ionic quenchers iodide and cesium showed opposite effects at different pH. In the case of cesium, raising the pH resulted in increased quenching and accessibility of typtophan residue, while the iodide showed just opposite effect. These studies showed that the single tryptophan residue of the lectin (per monomer) is relatively exposed, and might be in the vicinity of positively charged amino acid residues. Various amino acids of the F. solani lectin were modified using different reagents to obtain information about the hemagglutinating site. The chemical modification studies suggested tyrosine residues can be modified using N-acetylimidazole, which results in complete loss of hemagglutination activity of the lectin. Kinetics of chemical modification suggested involvement of only 2 tyrosine residues. Modification of arginine, cysteine, histidine, lysine, aspartate, glutamate and tryptophan did not result in loss of hemagglutinating activity of the lectin.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom3><style face="normal" font="default" size="100%">&lt;p&gt;Foreign&lt;/p&gt;</style></custom3><custom4><style face="normal" font="default" size="100%">1.966</style></custom4></record></records></xml>