A novel dimeric structure of the RimL Nalpha-acetyltransferase from Salmonella typhimurium.
RimL is responsible for converting the prokaryotic ribosomal protein from L12 to L7 by acetylation of its N-terminal amino group. We demonstrate that purified RimL is capable of posttranslationally acetylating L12, exhibiting a V(max) of 21 min(-1). We have also determined the apostructure of RimL from Salmonella typhimurium and its complex with coenzyme A, revealing a homodimeric oligomer with structural similarity to other Gcn5-related N-acetyltransferase superfamily members. A large central trough located at the dimer interface provides sufficient room to bind both L12 N-terminal helices. Structural and biochemical analysis indicates that RimL proceeds by single-step transfer rather than a covalent-enzyme intermediate. This is the first structure of a Gcn5-related N-acetyltransferase family member with demonstrated activity toward a protein N(alpha)-amino group and is a first step toward understanding the molecular basis for N(alpha)acetylation and its function in cellular regulation.
Vetting
Matthew W
MW
Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461-1602, USA.
de Carvalho
Luiz Pedro S
LP
Roderick
Steven L
SL
Blanchard
John S
JS
D000123:Acetyltransferases / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001426:Bacterial Proteins; D001665:Binding Sites; D002417:Cattle; D003001:Cloning, Molecular; D003065:Coenzyme A / Q000737:chemistry; D018360:Crystallography, X-Ray; D019281:Dimerization; D004926:Escherichia coli / Q000378:metabolism; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D020033:Protein Isoforms; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D012486:Salmonella typhimurium / Q000201:enzymology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D001426:Bacterial Proteins; D020033:Protein Isoforms; D000123:Acetyltransferases; C502453:RimL protein, Salmonella typhimurium; D003065:Coenzyme A