01980nas a2200217   4500008004100000022001400041245016600055210006900221260010300290300001600393490000800409520106400417100001801481700002501499700002101524700002401545700002001569700002401589700001901613856013001632       2006                        eng d  a0021-925800aStructural and functional analysis of a conjugated bile salt hydrolase from Bifidobacterium longum reveals an evolutionary relationship with penicillin V acylase0 aStructural and functional analysis of a conjugated bile salt hyd  a9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USAbAMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INCcOCT  a32516-325250 v2813 a<p>Bile salt hydrolase (BSH) is an enzyme produced by the intestinal microflora that catalyzes the deconjugation of glycine- or taurine-linked bile salts. The crystal structure of BSH reported here from Bifidobacterium longum reveals that it is a member of N-terminal nucleophil hydrolase structural superfamily possessing the characteristic alpha beta beta alpha tetra-lamellar tertiary structure arrangement. Site-directed mutagenesis of the catalytic nucleophil residue, however, shows that it has no role in zymogen processing into its corresponding active form. Substrate specificity was studied using Michaelis-Menten and inhibition kinetics and fluorescence spectroscopy. These data were compared with the specificity profile of BSH from Clostridium perfrigens and pencillin V acylase from Bacillus sphaericus, for both of which the three-dimensional structures are available. Comparative analysis shows a gradation in activity toward common substrates, throwing light on a possible common route toward the evolution of pencillin V acylase and BSH.</p>1 aKumar, Suresh1 aBrannigan, James, A.1 aPrabhune, Asmita1 aPundle, Archana, V.1 aDodson, Guy, G.1 aDodson, Eleanor, J.1 aSuresh, C., G.  uhttps://library.ncl.res.in/content/structural-and-functional-analysis-conjugated-bile-salt-hydrolase-bifidobacterium-longum-002107nas a2200241   4500008004100000022001400041245014100055210006900196260008600265300001200351490000700363520118300370653001601553653002401569653001901593653001401612100001801626700001901644700002501663700002001688700002501708856013201733       2007                        eng d  a1521-654300aBile salt hydrolase, the member of Ntn-hydrolase family: differential modes of structural and functional transitions during denaturation0 aBile salt hydrolase the member of Ntnhydrolase family differenti  a325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USAbTAYLOR & FRANCIS INCcFEB  a118-1250 v593 a<p>Conformational transitions and functional stability of the bile salt hydrolase (BSH; cholylglycine EC: 3.5.1.24) from Bifidobacterium longum (BlBSH) cloned and expressed in E. coli were studied under thermal, chemical and pH-mediated denaturation conditions using fluorescence and CD spectroscopy. Thermal and Gdn-HCl-mediated denaturation of BlBSH is a multistep process of inactivation and unfolding. The inactivation and unfolding of the enzyme was found to be irreversible. Enzyme activity seems sensitive to even minor conformational changes at the active site. Thermal denaturation as such did not result in any insoluble protein aggregates. However, on treating with 0.25-1 M Gdn-HCl the enzyme showed increasing aggregation at temperatures of 40-55 degrees C indicating more complex structural changes taking place in the presence of chemical denaturants. The enzyme secondary structure was still intact at acidic pH (pH 1-3). The perturbation in the tertiary structure at the acidic pH was detected through freshly formed solvent exposed hydrophobic patches on the enzyme. These changes could be due to the formation of an acid-induced molten globule-like state.</p>10aAggregation10aBile salt hydrolase10amolten-globule10aUnfolding1 aKumar, Suresh1 aSuresh, C., G.1 aBrannigan, James, A.1 aDodson, Guy, G.1 aGaikwad, Sushama, M.  uhttps://library.ncl.res.in/content/bile-salt-hydrolase-member-ntn-hydrolase-family-differential-modes-structural-and-functional02563nas a2200265   4500008004100000022001400041245011100055210006900166260007900235300001400314490000700328520157900335653002901914653001801943653002501961653002301986653002202009653002802031100001802059700002102077700001902098700003302117700001902150856012802169       2007                        eng d  a0141-022900aTryptophan residue is identified in the substrate binding of penicillin G acylase from Kluyvera citrophila0 aTryptophan residue is identified in the substrate binding of pen  a360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USAbELSEVIER SCIENCE INCcAPR  a1389-13970 v403 a<p>Penicillin acylases are important enzymes in pharmaceutical industry for the production of semi-synthetic beta-lactam antibiotics via the key intermediate 6-aminopenicillanic acid. The penicillin G acylase purified from Kluyvera citrophila (KcPGA) on modification with tryptophan-specific reagents such as N-bromo succinamide (NBS) and 2-hydroxy 5-nitrobenzylbromide (HNBB) showed partial loss of activity and substrate protection. Various solute quenchers and substrate were used to probe the microenvironment of the putative reactive tryptophan through fluorescence quenching. Homology modeling of KcPGA structure has been carried out. Docking substrate on this modeled KcPGA structure identifies the tryptophan residue that is directly influenced by substrate binding. To confirm the biological significance of this particular tryptophan, we did a sequence comparison of PGAs from various organisms. The sequence alignment clustered the matches into two sets, those closer to (&gt; 40% identical) KcPGA and had the tryptophan of interest present in them formed the first set, while those less identical (&lt; 30%) to KcPGA and the particular tryptophan absent in them formed the second set. It is clear from the reported kinetic parameters of representative members of these two sets that the affinity for penicillin G (penG) of the former class is several times better. Thus, based on our studies we suggest that the tryptophan residue in the identified position is important for binding substrate penG by the acylases. (c) 2006 Elsevier Inc. All rights reserved.</p>10afluorescence measurement10aK. citrophila10aPenicillin G acylase10asequence alignment10asubstrate-docking10atryptophan modification1 aKumar, Suresh1 aPrabhune, Asmita1 aPundle, A., V.1 aKarthikeyan, Muthukumarasamy1 aSuresh, C., G.  uhttps://library.ncl.res.in/content/tryptophan-residue-identified-substrate-binding-penicillin-g-acylase-kluyvera-citrophila01476nas 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-0