02160nas a2200289   4500008004100000022001400041245011900055210006900174260007500243300001200318490000700330520114000337653001201477653002601489653001801515653001901533653002401552653002001576653001401596100002001610700002501630700001901655700001801674700002001692700002701712856013101739       2011                        eng d  a1053-050900aConformational transitions in ariesaema curvatum lectin: characterization of an acid induced active molten globule0 aConformational transitions in ariesaema curvatum lectin characte  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScMAR  a753-7630 v213 a<p>Biophysical characterization of a lectin from Ariesaema curvatum (ACL) was carried out using steady state as well as time resolved fluorescence and CD spectroscopy under various denaturing conditions. An intermediate with altered tryptophan microenvironment was detected in the phase diagram, which exibited pronounced secondary structure and hemagglutinating activity in presence of 0.25 M Gdn-HCl. An acid induced molten- globule like structure possessing activity and higher thermostability was detected. Transition to the molten globule state was reversible in nature. The lectin retained hemagglutinating activity even after incubation at 95 A degrees C. Both chemical and thermal unfolding of the lectin were found to consist of multistate processes. Fluorescence quenching of ACL was strong with acrylamide and KI. The single tryptophan was found to be surrounded by high density of the positively charged amino acid residues as shown by a ten fold higher K(sv) for KI compared to that for CsCl. The average lifetime of tryptophan fluorescence increased from 1.24 ns in the native state to 1.72 ns in the denatured state.</p>10aAraceae10aFluorescence lifetime10aHemagglutinin10aMolten globule10aSecondary structure10aThermostability10aUnfolding1 aSharma, Urvashi1 aGaikwad, Sushama, M.1 aSuresh, C., G.1 aDhuna, Vikram1 aSingh, Jatinder1 aKamboj, Sukhdev, Singh  uhttps://library.ncl.res.in/content/conformational-transitions-ariesaema-curvatum-lectin-characterization-acid-induced-active-001476nas a2200289   4500008004100000022001400041245011400055210006900169260007600238300001200314490000700326520044800333653002000781653002200801653001900823653002200842653002000864653002000884100002900904700001800933700001900951700002100970700002000991700002401011700001901035856013201054       2012                        eng d  a1744-309100aCrystallization and X-ray structure analysis of a thermostable penicillin G acylase from alcaligenes faecalis0 aCrystallization and Xray structure analysis of a thermostable pe  aCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAbWILEY-BLACKWELLcMAR  a273-2770 v683 a<p>{The enzyme penicillin G acylase (EC 3.5.1.11) catalyzes amide-bond cleavage in benzylpenicillin (penicillin G) to yield 6-aminopenicillanic acid, an intermediate chemical used in the production of semisynthetic penicillins. A thermostable penicillin G acylase from Alcaligenes faecalis (AfPGA) has been crystallized using the hanging-drop vapour-diffusion method in two different space groups: C2221, with unit-cell parameters a = 72.9</p>10acalcium binding10adisulfide bridges10aNtn hydrolases10aorthorhombic form10atetragonal form10aThermostability1 aVarshney, Nishant, Kumar1 aKumar, Suresh1 aIgnatova, Zoya1 aPrabhune, Asmita1 aPundle, Archana1 aDodson, Eleanor, J.1 aSuresh, C., G.  uhttps://library.ncl.res.in/content/crystallization-and-x-ray-structure-analysis-thermostable-penicillin-g-acylase-alcaligenes-002736nas a2200277   4500008004100000022001400041245013100055210006900186260008000255300001400335490000700349520172600356653001702082653002802099653002302127653002102150653001402171653002302185653002002208100002602228700001802254700002202272700002602294700001902320856011902339       2015                        eng d  a1367-543500aSequence and structure-based comparative analysis to assess, identify and improve the thermostability of penicillin G acylases0 aSequence and structurebased comparative analysis to assess ident  aTIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANYbSPRINGER HEIDELBERGcNOV  a1493-15060 v423 a<p>Penicillin acylases are enzymes employed by the pharmaceutical industry for the manufacture of semi-synthetic penicillins. There is a continuous demand for thermostable and alkalophilic enzymes in such applications. We have carried out a computational analysis of known penicillin G acylases (PGAs) in terms of their thermostable nature using various protein-stabilizing factors. While the presence of disulfide bridges was considered initially to screen putative thermostable PGAs from the database, various other factors such as high arginine to lysine ratio, less content of thermolabile amino acids, presence of proline in beta-turns, more number of ion-pair and other non-bonded interactions were also considered for comparison. A modified consensus approach designed could further identify stabilizing residue positions by site-specific comparison between mesostable and thermostable PGAs. A most likely thermostable enzyme identified from the analysis was PGA from Paracoccus denitrificans (PdPGA). This was cloned, expressed and tested for its thermostable nature using biochemical and biophysical experiments. The consensus site-specific sequence-based approach predicted PdPGA to be more thermostable than Escherichia coli PGA, but not as thermostable as the PGA from Achromobacter xylosoxidans. Experimental data showed that PdPGA was comparatively less thermostable than Achromobacter xylosoxidans PGA, although thermostability factors favored a much higher stability. Despite being mesostable, PdPGA being active and stable at alkaline pH is an advantage. Finally, several residue positions could be identified in PdPGA, which upon mutation selectively could improve the thermostability of the enzyme.</p>10aAlkalistable10abeta-lactam antibiotics10aConsensus approach10aDisulfide bridge10aIon pairs10aPenicillin acylase10aThermostability1 aPanigrahi, Priyabrata1 aChand, Deepak1 aMukherji, Ruchira1 aRamasamy, Sureshkumar1 aSuresh, C., G.  uhttps://library.ncl.res.in/content/sequence-and-structure-based-comparative-analysis-assess-identify-and-improve-0