title: Design of novel synthetic MTS conjugates of bile acids for site-directed sulfhydryl labeling of cysteine residues in bile acid binding and transporting proteins.
abstract: The purpose of this study was to design bile acid-containing methanethiosulfonate (MTS) agents with appropriate physical attributes to effectively modify the cysteine residues present in the human apical sodium-dependent bile acid transporter. Four physical properties including surface area, molecular volume, ClogP, and dipole moment were calculated for each semiempirically optimized structure of MTS compounds. The specificity of the synthesized bile acid-MTS conjugate toward native cysteines and putative bile acid interacting domains of hASBT was supported by the effect of 1mM cholyl-MTS, cholylglycyl-MTS, and 3-amino-cholyl-MTS on uptake activity, that displayed a significant decrease in TCA affinity (K(T)=69.9+/-4.5, 69.01+/-6.2, and 63.24+/-0.26 microM and J(max)=35.8+/-0.3, 24.03+/-1.22, 46.49+/-5.01 pmol mg protein min(-1), respectively). These compounds prove to be effective tools in probing the structural and functional effects of cysteine residues in bile acid binding and transporting proteins.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA.
authors.forename: Abhijit
authors.initials: A
authors.lastname: Ray
authors.forename: Antara
authors.initials: A
authors.lastname: Banerjee
authors.forename: Cheng
authors.initials: C
authors.lastname: Chang
authors.forename: Chandra M
authors.initials: CM
authors.lastname: Khantwal
authors.forename: Peter W
authors.initials: PW
authors.lastname: Swaan
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism*; D001692:Biological Transport; D019556:COS Cells; D002352:Carrier Proteins; D002522:Chlorocebus aethiops; D003545:Cysteine / Q000737:chemistry* / Q000235:genetics; D015195:Drug Design; D005020:Ethyl Methanesulfonate / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins; D029363:Organic Anion Transporters, Sodium-Dependent / Q000737:chemistry / Q000378:metabolism*; D013329:Structure-Activity Relationship; D027981:Symporters / Q000737:chemistry / Q000378:metabolism*; D013656:Taurocholic Acid / Q000378:metabolism*
chemical_list: D001647:Bile Acids and Salts; D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D029363:Organic Anion Transporters, Sodium-Dependent; D027981:Symporters; C037643:bile acid binding proteins; C071908:sodium-bile acid cotransporter; D013656:Taurocholic Acid; D005020:Ethyl Methanesulfonate; D003545:Cysteine