title: Structural characterization of CalO1: a putative orsellinic acid methyltransferase in the calicheamicin-biosynthetic pathway.
abstract: The X-ray structure determination at 2.4 Å resolution of the putative orsellinic acid C3 O-methyltransferase (CalO1) involved in calicheamicin biosynthesis is reported. Comparison of CalO1 with a homology model of the functionally related calicheamicin orsellinic acid C2 O-methyltransferase (CalO6) implicates several residues that are likely to contribute to the regiospecificity of alkylation. Consistent with the proposed requirement of an acyl-carrier-protein-bound substrate, this structural study also reveals structural determinants within CalO1 that are anticipated to accommodate an association with an acyl carrier protein.
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Aram
authors.initials: A
authors.lastname: Chang
authors.forename: Shanteri
authors.initials: S
authors.lastname: Singh
authors.forename: Craig A
authors.initials: CA
authors.lastname: Bingman
authors.forename: Jon S
authors.initials: JS
authors.lastname: Thorson
authors.forename: George N
authors.initials: GN
authors.lastname: Phillips
mesh_terms: D000617:Aminoglycosides / Q000096:biosynthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008780:Methyltransferases / Q000737:chemistry* / Q000378:metabolism; D008847:Micromonospora / Q000201:enzymology*; D008958:Models, Molecular; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D012118:Resorcinols / Q000737:chemistry* / Q000378:metabolism; D040681:Structural Homology, Protein; D013379:Substrate Specificity
chemical_list: D000617:Aminoglycosides; D012118:Resorcinols; C501612:orsellinic acid; D008780:Methyltransferases