title: Synthesis and incorporation of [6,7]-selenatryptophan into dihydrofolate reductase.
abstract: Until recently, the only selenium containing amino acid which could be used to completely substitute for a wild type amino acid was selenomethionine (SeMet). In the last decade the preparation of SeMet containing proteins has proved to be valuable tools in the determination of three-dimensional structure by multiwavelength anomalous diffraction (MAD) techniques. The potential utility of a selenium containing tryptophan analog, beta-seleno[3,2-b]pyrrolyl-L-alanine ([4,5]selenatryptophan), has recently been demonstrated in the literature. This finding shows promise for the bioincorporation of its positional isomer, beta-selenolo[2,3-b]pyrrolyl-L-alanine ([6,7]selenatryptophan), thereby adding to the essential arsenal of selenium-containing amino acids for use in the characterization of proteins. The synthesis of [6,7]selenatryptophan by enzymatic biotransformation with tryptophan synthase from selenolo[2,3-b]pyrrole was carried out as well as its characterization by NMR spectroscopy and thin layer chromatography. Selenatryptophyl dihydrofolate reductase ([6,7]SeTrp-DHFR) was then synthesized in vivo, purified, and found to exhibit no perturbations to enzymatic activity.
authors.affiliation: Department of Chemistry, Tennessee Technological University, Cookeville 38505, USA. Jboles@tntech.edu
authors.forename: Jeffrey O
authors.initials: JO
authors.lastname: Boles
authors.forename: James
authors.initials: J
authors.lastname: Henderson
authors.forename: Duane
authors.initials: D
authors.lastname: Hatch
authors.forename: Louis A
authors.initials: LA
authors.lastname: Silks
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives / Q000032:analysis* / Q000096:biosynthesis* / Q000737:chemistry; D002855:Chromatography, Thin Layer; D008956:Models, Chemical; D016566:Organoselenium Compounds / Q000032:analysis* / Q000737:chemistry; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry*; D014367:Tryptophan Synthase / Q000378:metabolism
chemical_list: D016566:Organoselenium Compounds; C468292:beta-selenolo(2,3-b)pyrrolylalanine; D013762:Tetrahydrofolate Dehydrogenase; D014367:Tryptophan Synthase; D000409:Alanine