Download MendeleyStructural and Functional Studies of a gem-Dimethylating Methyltransferase from a trans-Acyltransferase Assembly Line.
Meinke, J.L., Mehaffey, M.R., Wagner, D.T., Sun, N., Zhang, Z., Brodbelt, J.S., Keatinge-Clay, A.T.(2018) ACS Chem Biol 13: 3306-3314
- PubMed: 30371052
- DOI: https://doi.org/10.1021/acschembio.8b00733
- Primary Citation of Related Structures:
6CCA - PubMed Abstract:
The methyl substituents in products of trans-acyltransferase assembly lines are usually incorporated by S-adenosyl-methionine (SAM)-dependent methyltransferase (MT) domains. The gem-dimethyl moieties within the polyketide disorazol are installed through the iterative action of an MT in the third module of its assembly line. The 1.75-Å-resolution crystal structure of this MT helps elucidate how it catalyzes the addition of two methyl groups. Activity assays of point mutants on β-ketoacyl chains linked to an acyl carrier protein and N-acetylcysteamine provide additional insights into the roles of active site residues. The replacement of an alanine with a phenylalanine at an apparent gatekeeping position resulted in more monomethylation than dimethylation. MTs may form an interface with ketoreductases (KRs) and even mediate the docking of trans-acyltransferase assembly line polypeptides through this association.
Organizational Affiliation:
Department of Molecular Biosciences , The University of Texas at Austin , Austin , Texas 78712 , United States.
