title: Structure of Arabidopsis thaliana At1g77540 protein, a minimal acetyltransferase from the COG2388 family.
abstract: We describe X-ray crystal and NMR solution structures of the protein coded for by Arabidopsis thaliana gene At1g77540.1 (At1g77540). The crystal structure was determined to 1.15 A with an R factor of 14.9% (Rfree = 17.0%) by multiple-wavelength anomalous diffraction using sodium bromide derivatized crystals. The ensemble of NMR conformers was determined with protein samples labeled with 15N and 13C + 15N. The X-ray structure and NMR ensemble were closely similar with rmsd 1.4 A for residues 8-93. At1g77540 was found to adopt a fold similar to that of GCN5-related N-acetyltransferases. Enzymatic activity assays established that At1g77540 possesses weak acetyltransferase activity against histones H3 and H4. Chemical shift perturbations observed in 15N-HSQC spectra upon the addition of CoA indicated that the cofactor binds and identified its binding site. The molecular details of this interaction were further elucidated by solving the X-ray structure of the At1g77540-CoA complex. This work establishes that the domain family COG2388 represents a novel class of acetyltransferase and provides insight into possible mechanistic roles of the conserved Cys76 and His41 residues of this family.
authors.affiliation: Center for Eukaryotic Structural Genomics, Biochemistry Department, College of Agricultural and Life Sciences, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin 53706-1544, USA.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Tyler
authors.forename: Eduard
authors.initials: E
authors.lastname: Bitto
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Berndsen
authors.forename: Craig A
authors.initials: CA
authors.lastname: Bingman
authors.forename: Shanteri
authors.initials: S
authors.lastname: Singh
authors.forename: Min S
authors.initials: MS
authors.lastname: Lee
authors.forename: Gary E
authors.initials: GE
authors.lastname: Wesenberg
authors.forename: John M
authors.initials: JM
authors.lastname: Denu
authors.forename: George N
authors.initials: GN
authors.lastname: Phillips
authors.forename: John L
authors.initials: JL
authors.lastname: Markley
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D001665:Binding Sites; D002384:Catalysis; D003065:Coenzyme A / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D051548:Histone Acetyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D040681:Structural Homology, Protein; D013379:Substrate Specificity
chemical_list: C516154:At1g77540 protein, Arabidopsis; D051548:Histone Acetyltransferases; D003065:Coenzyme A