Download MendeleyCrystal Structure of Rimi from Salmonella Typhimurium Lt2, the Gnat Responsible for N{Alpha}- Acetylation of Ribosomal Protein S18.
Vetting, M.W., Bareich, D.C., Yu, M., Blanchard, J.S.(2008) Protein Sci 17: 1781-1790
- PubMed: 18596200
- DOI: https://doi.org/10.1110/ps.035899.108
- Primary Citation of Related Structures:
2CNM, 2CNS, 2CNT - PubMed Abstract:
The three ribosomal proteins L7, S5, and S18 are included in the rare subset of prokaryotic proteins that are known to be N(alpha)-acetylated. The GCN5-related N-acetyltransferase (GNAT) protein RimI, responsible for the N(alpha)-acetylation of the ribosomal protein S18, was cloned from Salmonella typhimurium LT2 (RimI(ST)), overexpressed, and purified to homogeneity. Steady-state kinetic parameters for RimI(ST) were determined for AcCoA and a peptide substrate consisting of the first six amino acids of the target protein S18. The crystal structure of RimI(ST) was determined in complex with CoA, AcCoA, and a CoA-S-acetyl-ARYFRR bisubstrate inhibitor. The structures are consistent with a direct nucleophilic addition-elimination mechanism with Glu103 and Tyr115 acting as the catalytic base and acid, respectively. The RimI(ST)-bisubstrate complex suggests that several residues change conformation upon interacting with the N terminus of S18, including Glu103, the proposed active site base, facilitating proton exchange and catalysis.
Organizational Affiliation:
Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
