01853nas a2200265   4500008004100000022001400041245011100055210006900166260006900235300001000304490000800314520088600322653002701208653005001235653001501285653001801300653002201318653001501340100001701355700001801372700002701390700001901417700002001436856013101456       2011                        eng d  a1011-134400aFluorescence resonance energy transfer from tryptophan to folic acid in micellar media and deionised water0 aFluorescence resonance energy transfer from tryptophan to folic   aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcAPR  a16-210 v1033 a<p>The fluorescence resonance energy transfer (FRET) from tryptophan (Trp) to folic acid (FA) in aqueous sodiumdodecyl sulphate, cetyltrimethyl ammonium bromide, and Brij-35 as well as deionised water was investigated using steady state and time resolved fluorescence techniques. The data obtained from steady state fluorescence spectral studies and time resolved measurement indicated that the FRET from Trp to FA occurred most effectively in aqueous sodium dodecyl sulphate micellar solutions. The distance between Trp and FA were evaluated. Binding constant, number of binding sites and thermodynamic parameters were determined for Trp-FA interactions in deionised water. The values of the thermodynamic parameters suggest that the hydrophobic forces and hydrogen bonding are the key interacting forces between Trp-FA interaction. (C) 2011 Elsevier B.V. All rights reserved.</p>10aFluorescence quenching10aFluorescence resonance energy transfer (FRET)10aFolic acid10aFoster theory10aStern-Volmer plot10aTryptophan1 aMote, U., S.1 aPatil, S., R.1 aBhosale, Siddharth, H.1 aHan, Sung-Hwan1 aKolekar, G., B.  uhttps://library.ncl.res.in/content/fluorescence-resonance-energy-transfer-tryptophan-folic-acid-micellar-media-and-deionised-002464nas a2200217   4500008004100000022001400041245013200055210006900187260007500256300001400331490000700345520161200352653002701964653002201991653001702013653002002030653001502050100002502065700002502090856013102115       2014                        eng d  a1053-050900aTryptophan environment and functional characterization of a kinetically stable serine protease containing a polyproline II fold0 aTryptophan environment and functional characterization of a kine  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScSEP  a1363-13700 v243 a<p>The single tryptophan residue from Nocardiopsis sp. serine protease (NprotI) was studied for its microenvironment using steady state and time-resolved fluorescence. The emission maximum was observed at 353 nm with excitation at 295 nm indicating tryptophan to be solvent exposed. Upon denaturation with 6 M guanidinum thiocyanate (GuSCN) the emission maxima was shifted to 360 nm. Solute quenching studies were performed with neutral (acrylamide) and ionic (I- and Cs+) quenchers to probe the exposure and accessibility of tryptophan residue of the protein. Maximum quenching was observed with acrylamide. In the native state, quenching was not observed with Cs+ indicating presence of only positively charged environment surrounding tryptophan. However; in denatured protein, quenching was observed with Cs+, indicating charge reorientation after denaturation. No quenching was observed with Cs+ even at pH 1.0 or 10.0; while at acidic pH, a higher rate of quenching was observed with KI. This indicated presence of more positive charge surrounding tryptophan at acidic pH. In time resolved fluorescence measurements, the fluorescence decay curves could be best fitted to monoexponential pattern with lifetimes of 5.13 ns for NprotI indicating one conformer of the trp. Chemical modification studies with phenyl glyoxal suggested presence of Arg near the active site of the enzyme. No inhibition was seen with soyabean trypsin and limabean inhibitors, while, CanPI uncompetitively inhibited NprotI. Various salts from Hofmeister series were shown to decrease the activity and PPII content of NprotI.</p>10aFluorescence quenching10aHofmeister series10aNocardiopsis10aSerine protease10aTryptophan1 aRohamare, Sonali, B.1 aGaikwad, Sushama, M.  uhttps://library.ncl.res.in/content/tryptophan-environment-and-functional-characterization-kinetically-stable-serine-protease-002418nas a2200253   4500008004100000022001400041245010700055210006900162260007300231300001200304490000700316520147800323653001601801653002001817653002701837653004101864653001401905100002101919700001801940700002701958700002701985700002502012856012702037       2016                        eng d  a0141-813000aFunctional and conformational transitions of mevalonate diphosphate decarboxylase from Bacopa monniera0 aFunctional and conformational transitions of mevalonate diphosph  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB  a160-1700 v833 a<p>Functional and conformational transitions of mevalonate diphosphate decarboxylase (MDD), a key enzyme of mevalonate pathway in isoprenoid biosynthesis, from Bacopa monniera (BmMDD), cloned and overexpressed in Escherichia coli were studied under thermal, chemical and pH-mediated denaturation conditions using fluorescence and Circular dichroism spectroscopy. Native BmMDD is a helix dominant structure with 45% helix and 11% sheets and possesses seven tryptophan residues with two residues exposed on surface, three residues partially exposed and two situated in the interior of the protein. Thermal denaturation of BmMDD causes rapid structural transitions at and above 40 degrees C and transient exposure of hydrophobic residues at 50 degrees C, leading to aggregation of the protein. An acid induced molten globule like structure was observed at pH 4, exhibiting altered but compact secondary structure, distorted tertiary structure and exposed hydrophobic residues. The molten globule displayed different response at higher temperature and similar response to chemical denaturation as compared to the native protein. The surface tryptophans have predominantly positively charged amino acids around them, as indicated by higher K-SV for IC as compared to that for CsCl. The native enzyme displayed two different lifetimes, vi (1.203 +/- 0.036 ns) and tau 2 (3.473 +/- 0.12 ns) indicating two populations of tryptophan. (C) 2015 Elsevier B.V. All rights reserved.</p>10aAggregation10aCD spectroscopy10aFluorescence quenching10aMevalonate diphosphate decarboxylase10aUnfolding1 aShakeel, Abbassi1 aPatel, Krunal1 aKhan, Bashir, Mohammad1 aBhosale, Siddharth, H.1 aGaikwad, Sushama, M.  uhttps://library.ncl.res.in/content/functional-and-conformational-transitions-mevalonate-diphosphate-decarboxylase-bacopa-0