title: Macrolactamization of glycosylated peptide thioesters by the thioesterase domain of tyrocidine synthetase.
abstract: The 35 kDa thioesterase (TE) domain excised from the megadalton tyrocidine synthetase (Tyc Syn) retains autonomous capacity to macrocyclize peptidyl thioesters to D-Phe1-L-Leu10-macrolactams. Since a number of nonribosomal peptides undergo O-glycosylation events during tailoring to gain biological activity, the Tyc Syn TE domain was evaluated for cyclization capacity with glycosylated peptidyl-S-NAC substrates. First, Tyr7 was replaced with Tyr(beta-D-Gal) and Tyr(beta-D-Glc) as well as with Ser-containing beta-linked D-Gal, D-Glc, D-GlcNAc, and D-GlcNH2, and these new analogs were shown to be cyclized with comparable kcat/Km catalytic efficiency. Similarly, Gal- or tetra-O-acetyl-Gal-Ser could also be substituted at residues 5, 6, and 8 in the linear decapeptidyl-S-NAC sequences and cyclized without substantial loss in catalytic efficiency by Tyc Syn TE. The cyclic glycopeptides retained antibiotic activity as membrane perturbants in MIC assays, opening the possibility for library construction of cyclic glycopeptides by enzymatic macrocyclization.
authors.affiliation: Department of Biological Chemistry, and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Hening
authors.initials: H
authors.lastname: Lin
authors.forename: Desiree A
authors.initials: DA
authors.lastname: Thayer
authors.forename: Chi-Huey
authors.initials: CH
authors.lastname: Wong
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Walsh
mesh_terms: D001412:Bacillus subtilis / Q000187:drug effects; D020134:Catalytic Domain; D003500:Cyclization; D004353:Drug Evaluation, Preclinical; D004912:Erythrocytes / Q000187:drug effects; D004952:Esters / Q000138:chemical synthesis* / Q000737:chemistry; D006031:Glycosylation; D006801:Humans; D007700:Kinetics; D007769:Lactams / Q000138:chemical synthesis* / Q000737:chemistry; D047028:Macrocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D010453:Peptide Synthases / Q000737:chemistry*; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D013379:Substrate Specificity; D013869:Thiolester Hydrolases / Q000737:chemistry*; D014440:Tyrocidine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D004952:Esters; D007769:Lactams; D047028:Macrocyclic Compounds; D010455:Peptides; D014440:Tyrocidine; D013869:Thiolester Hydrolases; D010453:Peptide Synthases; C035180:tyrocidine synthetase