Structural and Functional Studies of a gem-Dimethylating Methyltransferase from a trans-Acyltransferase Assembly Line
- Resource Type
- Authors
- M. Rachel Mehaffey; Jennifer S. Brodbelt; Zhicheng Zhang; Jessica L. Meinke; Adrian T. Keatinge-Clay; Drew T. Wagner; Ningze Sun
- Source
- ACS Chemical Biology. 13:3306-3314
- Subject
- Models, Molecular
0301 basic medicine
Stereochemistry
Protein domain
Sequence alignment
Crystallography, X-Ray
010402 general chemistry
Methylation
01 natural sciences
Biochemistry
Article
03 medical and health sciences
Polyketide
Bacterial Proteins
Protein Domains
Catalytic Domain
Transferase
Amino Acid Sequence
Myxococcales
Oxazoles
Alanine
Molecular Structure
biology
Chemistry
Active site
Methyltransferases
General Medicine
0104 chemical sciences
Alcohol Oxidoreductases
Acyl carrier protein
030104 developmental biology
Polyketides
Acyltransferase
Mutation
biology.protein
Molecular Medicine
Polyketide Synthases
Sequence Alignment
Protein Binding
- Language
- ISSN
- 1554-8937
1554-8929
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.