02656nas a2200253   4500008004100000022001400041245014200055210006900197260009900266300001400365490000700379520163400386653002402020653004402044653001702088653002402105653002402129100001702153700002602170700002002196700003002216700002602246856013002272       2006                        eng d  a1359-511300aPurification, characterization and substrate specificity of thermostable alpha-galactosidase from Bacillus stearothermophilus (NCIM-5146)0 aPurification characterization and substrate specificity of therm  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcJUN  a1311-13170 v413 a<p>An extracellular thermostable alpha-galactosidase from Bacillus stearothermophilus (NCIM-5146) has been purified to homogeneity by chromatographic step, using Phenyl Sepharose CL-4B column. The specific activity of the enzyme was increased approximately 389-fold, from 1.03 U/mg protein to 400 U/mg protein. The molecular mass of the purified enzyme as determined by SDS-PAGE and gel filtration was 79.9 and 165.9 kDa, respectively, suggesting dimeric nature. The purified alpha-galactosidase is a non-glycosylated protein with a pI of 4.9. The pH and temperature optima for the purified enzyme are 6.5-7.0 and 65 degrees C, respectively. The alpha-galactosidase is stable over a broad pH range (3-9) and its half-life of inactivation (t(1/2)) at 70 degrees C is 30 min. The partial N-terminal sequence of alpha-galactosidase showed remarkable homology (80% similarity) with earlier reported alpha-galactosidase from B. stearothermophilus NUB 3621. The secondary structure of the enzyme determined by circular dichroism (CD) spectroscopy exhibited alpha/beta class of protein and showed temperature induced conformational forms below and above the transition temperature. The purified enzyme showed biphasic Arrhenius plot with break point at 55 degrees C for pNPG and 50 degrees C for melibiose, raffinose and stachyose. The enzyme hydrolyzes alpha-1-3, alpha-1-4, and alpha-1-6 galactosidic linkages and not the beta-galactosidic linkages. Synthetic substrates pNPG and oNPG had lower K-m and higher K-cat as compare to natural substrates, melibiose, raffinose, and stachyose. (c) 2006 Elsevier Ltd. All rights reserved.</p>10aalpha-galactosidase10aBacillus stearothermophilus (NCIM-5146)10aPurification10aSecondary structure10athermostable enzyme1 aGote, M., M.1 aKhan, Mohammad, Islam1 aGokhale, D., V.1 aBastawade, Kulbhushan, B.1 aKhire, Jayant, Malhar  uhttps://library.ncl.res.in/content/purification-characterization-and-substrate-specificity-thermostable-alpha-galactosidase-001652nas a2200217   4500008004100000022001400041245008300055210006900138260007300207300001200280490000700292520085400299653002301153653003501176653002401211100001901235700001901254700002601273700002501299856011001324       2008                        eng d  a0141-813000aStructure-activity relationship of a hemagglutinin from Moringa oleifera seeds0 aStructureactivity relationship of a hemagglutinin from Moringa o  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR  a203-2070 v423 a<p>The hemagglutinin from the seeds of Moringa oleifera (MoL) agglutinates human as well as rabbit erythrocytes; the affinity for the latter is almost 250 times more than that for the former. MoL was inhibited by glycoproteins namely thyroglobulin, fetuin and holotransferin indicating the complex sugar specificity of the lectin. The protein is a homodimer with molecular mass of 14 kDa, subunits (7.1 kDa) linked by the disulfide bond(s). The secondary structure elements of MoL area-helix, 28%; beta-sheet, 23%; turn 20% and unordered 28%. While the activity and secondary structure were not affected at extreme pH and high temperature, they were drastically affected in presence of dithiothreitol at and above pH 7.0, indicating that disulfide linkages hold the active conformation of the protein. (C) 2007 Elsevier B.V. All rights reserved.</p>10adisulfide linkages10aMoringa oleifera hemagglutinin10aSecondary structure1 aKatre, Uma, V.1 aSuresh, C., G.1 aKhan, Mohammad, Islam1 aGaikwad, Sushama, M.  uhttps://library.ncl.res.in/content/structure-activity-relationship-hemagglutinin-moringa-oleifera-seeds-002108nas a2200277   4500008004100000022001400041245011500055210006900170260007500239300001200314490000700326520110400333653002001437653001701457653001701474653002601491653002401517100002401541700002501565700001901590700001801609700002601627700002001653700002701673856013001700       2009                        eng d  a1053-050900aComparative studies of two araceous lectins by steady state and time-resolved fluorescence and CD spectroscopy0 aComparative studies of two araceous lectins by steady state and   a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScMAR  a239-2480 v193 a<p>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.</p>10aAraceae lectins10aDenaturation10afluorescence10aLifetime spectroscopy10aSecondary structure1 aDharker, Poorva, N.1 aGaikwad, Sushama, M.1 aSuresh, C., G.1 aDhuna, Vikram1 aKhan, Mohammad, Islam1 aSingh, Jatinder1 aKamboj, Sukhdev, Singh  uhttps://library.ncl.res.in/content/comparative-studies-two-araceous-lectins-steady-state-and-time-resolved-fluorescence-and-0