<?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%">Shashidhara, K. S.</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%">Fluorescence quenching and time-resolved fluorescence studies of alpha-Mannosidase from Aspergillus fischeri (NCIM 508)</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%">alpha-Mannosidase</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</style></keyword><keyword><style  face="normal" font="default" size="100%">Solute quenching</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">NOV</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">6</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%">17</style></volume><pages><style face="normal" font="default" size="100%">599-605</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Apart from the vital role in glycoprotein biosynthesis and degradation, alpha-mannosidase is currently an important therapeutic target for the development of anticancer agents. Fluorescence quenching and time-resolved fluorescence of alpha-mannosidase, a multitryptophan protein from Aspergillus fischeri were carried out to investigate the tryptophan environment. The tryptophans were found to be differentially exposed to the solvent and were not fully accessible to the neutral quencher indicating heterogeneity in the environment. Quenching of the fluorescence by acrylamide was collisional. Surface tryptophans were found to have predominantly positively charged amino acids around them and differentially accessible to the ionic quenchers. Denaturation led to more exposure of tryptophans to the solvent and consequently in the significant increase in quenching with all the quenchers. The native enzyme showed two different lifetimes, tau (1) (1.51 ns) and tau (2) (5.99 ns). The average lifetime of the native protein (tau) (3.187 ns) was not affected much after denaturation (tau) (3.219 ns), while average lifetime of the quenched protein samples was drastically reduced (1.995 ns for acrylamide and 1.537 ns for iodide). This is an attempt towards the conformational studies of alpha-mannosidase.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><work-type><style face="normal" font="default" size="100%">Article</style></work-type><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">1.601</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%">Shashidhara, K. S.</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%">Class II alpha-mannosidase from aspergillus fischeri: energetics of catalysis and inhibition</style></title><secondary-title><style face="normal" font="default" size="100%">International Journal of Biological Macromolecules</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">alpha-Mannosidase</style></keyword><keyword><style  face="normal" font="default" size="100%">Energy of activation</style></keyword><keyword><style  face="normal" font="default" size="100%">kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Swainsonine</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%">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%">ELSEVIER SCIENCE BV</style></publisher><pub-location><style face="normal" font="default" size="100%">PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS</style></pub-location><volume><style face="normal" font="default" size="100%">44</style></volume><pages><style face="normal" font="default" size="100%">112-115</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Energetics of the catalysis of Class II alpha-mannosidase (E.C.3.2.1.24) from Aspergillus fischeri was studied. The enzyme showed K(cat)/K(m) for Man (alpha 1-3) Man, Man (alpha 1-2) Man and Man (alpha 1-6) Man as 7488, 5376 and 3690 M(-1) min(-1), respectively. The activation energy, Ea was 15.14, 47.43 and 71.21 kJ/mol for a1-3, alpha 1-2 and alpha 1-6 linked mannobioses, respectively, reflecting the energy barrier in the hydrolysis of latter two substrates. The enzyme showed K(cat)/K(m) as 3.56 x 10(5) and 4.61 x 10(5) M(-1) min(-1) and E(a) as 38.7 and 8.92 kJ/mol, towards pNP alpha Man and 4-MeUmb alpha Man, respectively. Binding of Swainsonine to the enzyme is stronger than that of 1-deoxymannojirimycin. (C) 2008 Elsevier B.V. All rights reserved.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">2.502</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%">Shashidhara, K. S.</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%">Conformational and functional transitions in class II alpha-mannosidase from aspergillus fischeri</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%">Aggregation</style></keyword><keyword><style  face="normal" font="default" size="100%">alpha-Mannosidase</style></keyword><keyword><style  face="normal" font="default" size="100%">ANS binding</style></keyword><keyword><style  face="normal" font="default" size="100%">Circular dichroism</style></keyword><keyword><style  face="normal" font="default" size="100%">fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">GdnHCl</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrobicity</style></keyword><keyword><style  face="normal" font="default" size="100%">Thermal denaturation</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%">JUL</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">4</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%">827-836</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 conformational transitions in an oligomeric and high molecular weight class II alpha-mannosidase from Aspergillus fischeri were examined using fluorescence and CD spectroscopy under chemical, thermal and acid denaturing conditions. The enzyme lost the activity first and then the overall folded conformation and secondary structure. The midpoint values of GdnHCl mediated changes measured by inactivation; fluorescence and negative ellipticity were 0.48 M, 1.5 M and 1.9 M, respectively. The protein almost completely unfolded in 4.0 M GdnHCl but not at 90 A degrees C. The inactivation and unfolding were irreversible. At pH 2.0, the protein exhibited molten-globule like intermediate with rearranged secondary and tertiary structures and exposed hydrophobic amino acids on the surface. This species showed increased accessibility of Trp to the quenchers and got denatured with GdnHCl in a different manner. The insoluble aggregates of a thermally denatured protein could be detected only in the presence of 0.25-0.75 M GdnHCl.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">4</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%">Kumar, Avinash</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%">Multistate unfolding of alpha-mannosidase from Canavalia ensiformis (Jack Bean): evidence for the thermostable molten globule</style></title><secondary-title><style face="normal" font="default" size="100%">Biochemical and Biophysical Research Communications</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">alpha-Mannosidase</style></keyword><keyword><style  face="normal" font="default" size="100%">Circular dichroism</style></keyword><keyword><style  face="normal" font="default" size="100%">fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">Guanidine hydrochloride</style></keyword><keyword><style  face="normal" font="default" size="100%">Molten globule</style></keyword><keyword><style  face="normal" font="default" size="100%">Thermostability</style></keyword><keyword><style  face="normal" font="default" size="100%">Unfolding</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%">DEC</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">3-4</style></number><publisher><style face="normal" font="default" size="100%">ACADEMIC PRESS INC ELSEVIER SCIENCE</style></publisher><pub-location><style face="normal" font="default" size="100%">525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA</style></pub-location><volume><style face="normal" font="default" size="100%">403</style></volume><pages><style face="normal" font="default" size="100%">391-397</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 relevance of partially ordered states of proteins (such as the molten-globule state) in cellular processes is beginning to be understood. We examined the conformational transitions in a multimeric and high molecular weight class II alpha-mannosidase from Canavalia ensiformis (Jack Bean) (Jb alpha-man) utilizing intrinsic fluorescence, solute quenching, hydrophobic dye binding, size exclusion chromatography and circular dichroism (CD) spectroscopy for the protein in presence of Guanidine hydrochloride (GdnHCl). The decomposition analysis of the protein spectra obtained during unfolding showed progressive appearance of class S, I, II and III trp. The parameter A and spectral center of mass showed multi state unfolding of the protein and phase diagram analysis revealed formation of an intermediate of Jb alpha-man in the vicinity of 1 M GdnHCl. The intermediate exhibited compact secondary and distorted tertiary structure with exposed hydrophobic amino acids on the surface, indicating the molten-globule nature. The dissociation, partial unfolding and aggregation of Jb alpha-man occurred simultaneously during chemical denaturation. The molten-globule possessed slightly higher hydrodynamic radius, perturbance in the structure up to 60 degrees C and stability of the structure up to 80 degrees C unlike the native Jack Bean alpha-mannosidase. The modes of chemical and thermal denaturation of the native protein were different. The solute quenching parameters confirmed the altered confirmation of the intermediate. Taken together, our results constitute one of the early reports of formation of GdnHCl induced molten globule in a class II alpha-mannosidase. (C) 2010 Elsevier Inc. All rights reserved.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3-4</style></issue><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">2.595</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%">Kumar, Avinash</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%">Jack bean alpha-mannosidase (Jb alpha-man): tolerance to alkali, chelating and reducing agents and energetics of catalysis and inhibition</style></title><secondary-title><style face="normal" font="default" size="100%">International Journal of Biological Macromolecules</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Alkali tolerance</style></keyword><keyword><style  face="normal" font="default" size="100%">alpha-Mannosidase</style></keyword><keyword><style  face="normal" font="default" size="100%">beta-Mercaptoethanol</style></keyword><keyword><style  face="normal" font="default" size="100%">Energetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Inhibition</style></keyword><keyword><style  face="normal" font="default" size="100%">Metalloenzyme</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">DEC</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">5</style></number><publisher><style face="normal" font="default" size="100%">ELSEVIER SCIENCE BV</style></publisher><pub-location><style face="normal" font="default" size="100%">PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS</style></pub-location><volume><style face="normal" font="default" size="100%">49</style></volume><pages><style face="normal" font="default" size="100%">1066-1071</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Investigations of the catalytic and structural transitions of jack bean alpha-mannosidase (Jb alpha-man) are described in the present paper. The enzyme was maximally stable at pH 5.0; however, when incubated in the pH range of 11.0-12.0, showed 1.3 times higher activity and also stability for longer time. The free amino group at or near the active site was probably involved in the stability and activation mechanism. The active site is constituted by the association of two unidentical subunits connected by disulfide linkages. The metalloenzyme has Zn(2+) ions tightly bound and chelation reduces the thermal stability of the protein. Energetics of catalysis and thermodynamics of inhibition of the enzyme were also carried out. (C) 2011 Elsevier B.V. All rights reserved.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">5</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%">3.09</style></custom4></record></records></xml>