02249nas a2200253 4500008004100000022001400041245019300055210006900248260007900317300001400396490000700410520123900417653001601656653002401672653003201696653001601728653002601744653001101770653001501781100001701796700002601813700002601839856013001865 2007 eng d a0141-022900aActive site directed chemical modification of alpha-galactosidase from bacillus stearothermophilus (NCIM 5146): involvement of lysine, tryptophan and carboxylate residues in catalytic site0 aActive site directed chemical modification of alphagalactosidase a360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USAbELSEVIER SCIENCE INCcAPR a1312-13200 v403 a

The catalytic amino acid residues of the extracellular a-galactosidase (alpha-D-galactoside galactohydrolase; EC 3.2.1.22) from Bacillus stearothermophilus NCIM 5146 were investigated by pH dependence and chemical modification studies. These results suggested that carboxylate and a lysine residue take part in catalysis and only lysine residues were essential for substrate binding. Carbodiimide mediated chemical modification of the enzyme also supported that a carboxylate residue located in the active site act as a nucleophile base in substrate cleavage. Acylation and reductive methylation of lysine residues by acetic, citraconic anhydride and sodium borohydride suggested that four protonated lysine residues carrying positive charge on its epsilon-amino group provides the positive charge density for binding of the substrate. Additionally four tryptophan residues also found near to the active site and in a moderately hydrophobic environment. Kinetic and thermal inactivation study of modified enzyme indicated that these tryptophan residues might have a role in the catalytic site as well as in the thermal stabilization of active site conformation at higher temperature. (c) 2006 Elsevier Inc. All rights reserved.

10aActive site10aalpha-galactosidase10aBacillus stearothermophilus10acarboxylate10aChemical modification10alysine10aTryptophan1 aGote, M., M.1 aKhan, Mohammad, Islam1 aKhire, Jayant, Malhar uhttps://library.ncl.res.in/content/active-site-directed-chemical-modification-alpha-galactosidase-bacillus-stearothermophilus01853nas 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

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.

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

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.

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-001634nas a2200217 4500008004100000022001400041245011900055210006900174260000800243300001200251490000600263520088000269653001301149653002301162653002101185653001801206653001501224100002301239700002601262856012801288 2018 eng d a2365-654900aNovel pentadecyl phenol-tagged L-tryptophan molecules: synthesis, self- assembly and liquid crystalline properties0 aNovel pentadecyl phenoltagged Ltryptophan molecules synthesis se cJAN a108-1150 v33 a

The paper describes the self-assembly and liquid crystalline properties of pentadecylphenol tagged L-tryptophan molecules having ester and amide functionality. We have synthesized a series of molecules having mono and ditryptophan moieties attached to pentadecylphenol through amide or ester linkage. The fluorescence properties of the Boc-L-tryptophan-pentadecylphenol molecules were measured in methanol and found to aggregate beyond the critical aggregation concentration and self-assembled to give spherical structures. Upon deprotection of Boc group, the amine end group got involved in extended hydrogen bonding and fibril like structures were developed. These molecules also showed liquid crystalline behavior in hydrogen bonding solvents such as benzyl alcohol and showed needle like crystals in tert-butanol, as analyzed by polarized optical light microscopy.

10aCardanol10aliquid crystalline10apentadecylphenol10aSelf-assembly10aTryptophan1 aParappurath, Akhil1 aAbraham, Jancy, Nixon uhttps://library.ncl.res.in/content/novel-pentadecyl-phenol-tagged-l-tryptophan-molecules-synthesis-self-assembly-and-liquid02384nas a2200253 4500008004100000022001400041245011400055210006900169260000800238300001000246490000700256520154000263653002001803653002001823653001301843653001501856653001501871100002101886700002001907700003001927700002201957700002601979856012502005 2022 eng d a1075-261700aTryptophan-cardanol fluorescent nanoparticles inhibit alpha-synuclein aggregation and disrupt amyloid fibrils0 aTryptophancardanol fluorescent nanoparticles inhibit alphasynucl cAPR ae33740 v283 a

Protein misfolding and aggregation play a vital role in several human diseases such as Parkinson's, Alzheimer's, and prion diseases. The development of nanoparticles that modulate aggregation could be potential drug candidates for these neurodegenerative disorders. Parkinson's disease pathogenesis is closely associated with the accumulation of alpha-synuclein oligomers and fibrils in the substantia nigra of the brain. This report discusses the interactions of novel tryptophan-cardanol nanoparticles with alpha-synuclein protein monomers and fibrils. These nanoparticles could effectively disrupt alpha-synuclein fibrils and inhibit fibril formation at low concentrations such as 5 mu M. The tryptophan-cardanol nanoparticles inhibit fibril formation from unstructured protein resulting in spherical nanostructures. These nanoparticles could also disassemble amyloid fibrils; the complete disappearance of fibrils was evident after 48 h of incubation with tryptophan-cardanol. The transmission electron microscopy (TEM) micrographs after the incubation did not show any remnants of the peptide aggregates or oligomers. The thioflavin T fluorescence after the disassembly was diminished compared with that of fibrils also supports the inhibitory effect of the nanoparticles. Also, these nanoparticles did not reduce the viability of the SH-SY5Y cells. These findings suggest that the tryptophan-cardanol nanoparticles showed sufficiently high inhibitory activity and may have therapeutic potential for synucleinopathies.

10aalpha-synuclein10aamyloid fibrils10aCardanol10ainhibitors10aTryptophan1 aSunny, Lisni, P.1 aSrikanth, Priya1 aSunitha, Anju, Kunhiraman1 aTembulkar, Niyoti1 aAbraham, Jancy, Nixon uhttps://library.ncl.res.in/content/tryptophan-cardanol-fluorescent-nanoparticles-inhibit-alpha-synuclein-aggregation-and