title: Chemoenzymatic synthesis of peptidyl 3,4-dihydroxyphenylalanine for structure-activity relationships in marine invertebrate polypeptides.
abstract: An improved method for hydroxylating tyrosine-containing sequences in polypeptides to peptidyl 3,4-dihydroxyphenylalanine (DOPA) using mushroom tyrosinase at relatively high enzyme-to-substrate ratios is described. The new method involves incorporating borate into the reaction mixture to stop formation of the unwanted side product 3,4,5-trihydroxyphenylalanine. Using this method, a model for the palindromic central sequence for the antimicrobial peptide family, the styelins, Y*Y*KHKY*Y* (where Y* is DOPA), was successfully synthesized in high yield from YYKHKYY. This sequence represents a particularly challenging target because of the cluster of four precursor tyrosine residues are in close proximity. The method should be readily applied to larger polypeptides produced by either solid-phase synthesis or recombinant techniques and give greater insight into the roles of this unusual posttranslational modification in marine invertebrates such as mussels and ascidians.
authors.affiliation: Center for Marine Biotechnology and Biomedicine, University of California, San Diego, La Jolla, California, 92093-0204, USA. taylors@mitokor.com
authors.forename: Steven W
authors.initials: SW
authors.lastname: Taylor
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000737:chemistry; D004295:Dihydroxyphenylalanine / Q000138:chemical synthesis* / Q000737:chemistry*; D010455:Peptides / Q000138:chemical synthesis*; D013329:Structure-Activity Relationship; D014561:Urochordata / Q000737:chemistry
chemical_list: D010455:Peptides; D004295:Dihydroxyphenylalanine