title: Structural Characterization of CalS8, a TDP-α-D-Glucose Dehydrogenase Involved in Calicheamicin Aminodideoxypentose Biosynthesis.
abstract: Classical UDP-glucose 6-dehydrogenases (UGDHs; EC 1.1.1.22) catalyze the conversion of UDP-α-d-glucose (UDP-Glc) to the key metabolic precursor UDP-α-d-glucuronic acid (UDP-GlcA) and display specificity for UDP-Glc. The fundamental biochemical and structural study of the UGDH homolog CalS8 encoded by the calicheamicin biosynthetic gene is reported and represents one of the first studies of a UGDH homolog involved in secondary metabolism. The corresponding biochemical characterization of CalS8 reveals CalS8 as one of the first characterized base-permissive UGDH homologs with a >15-fold preference for TDP-Glc over UDP-Glc. The corresponding structure elucidations of apo-CalS8 and the CalS8·substrate·cofactor ternary complex (at 2.47 and 1.95 Å resolution, respectively) highlight a notably high degree of conservation between CalS8 and classical UGDHs where structural divergence within the intersubunit loop structure likely contributes to the CalS8 base permissivity. As such, this study begins to provide a putative blueprint for base specificity among sugar nucleotide-dependent dehydrogenases and, in conjunction with prior studies on the base specificity of the calicheamicin aminopentosyltransferase CalG4, provides growing support for the calicheamicin aminopentose pathway as a TDP-sugar-dependent process.
authors.affiliation: From the Center for Pharmaceutical Research and Innovation, University of Kentucky College of Pharmacy, Lexington, Kentucky 40536-0596.
authors.forename: Shanteri
authors.initials: S
authors.lastname: Singh
authors.affiliation: the Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439.
authors.forename: Karolina
authors.initials: K
authors.lastname: Michalska
authors.affiliation: the Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439.
authors.forename: Lance
authors.initials: L
authors.lastname: Bigelow
authors.affiliation: the Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439.
authors.forename: Michael
authors.initials: M
authors.lastname: Endres
authors.affiliation: the School of Pharmacy, University of Maryland Eastern Shore, Princess Anne, Maryland 21853.
authors.forename: Madan K
authors.initials: MK
authors.lastname: Kharel
authors.affiliation: the Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439.
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Babnigg
authors.affiliation: the Department of BioSciences, Department of Chemistry, Rice University, Houston, Texas 77005.
authors.forename: Ragothaman M
authors.initials: RM
authors.lastname: Yennamalli
authors.affiliation: the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, and.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Bingman
authors.affiliation: the Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Joachimiak
authors.affiliation: From the Center for Pharmaceutical Research and Innovation, University of Kentucky College of Pharmacy, Lexington, Kentucky 40536-0596, jsthorson@uky.edu.
authors.forename: Jon S
authors.initials: JS
authors.lastname: Thorson
authors.affiliation: the Department of BioSciences, Department of Chemistry, Rice University, Houston, Texas 77005 the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, and georgep@rice.edu.
authors.forename: George N
authors.initials: GN
authors.lastname: Phillips
mesh_terms: D000595:Amino Acid Sequence; D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D042843:Glucose 1-Dehydrogenase / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010429:Pentoses / Q000096:biosynthesis* / Q000737:chemistry; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D010429:Pentoses; D042843:Glucose 1-Dehydrogenase
keywords: UDP-glucose dehydrogenase (UGDH); biosynthesis; calicheamicin; carbohydrate; crystal structure; dehydrogenase; deoxysugar; enediyne; natural product; sugar nucleotide