Structure of Mesorhizobium loti arylamine N-acetyltransferase 1.
The arylamine N-acetyltransferase (NAT) enzymes have been found in a broad range of both eukaryotic and prokaryotic organisms. The NAT enzymes catalyse the transfer of an acetyl group from acetyl Co-enzyme A onto the terminal nitrogen of a range of arylamine, hydrazine and arylhydrazine compounds. Recently, several NAT structures have been reported from different prokaryotic sources including Salmonella typhimurium, Mycobacterium smegmatis and Pseudomonas aeruginosa. Bioinformatics analysis of the Mesorhizobium loti genome revealed two NAT paralogues, the first example of multiple NAT isoenzymes in a eubacterial organism. The M. loti NAT 1 enzyme was recombinantly expressed and purified for X-ray crystallographic studies. The purified enzyme was crystallized in 0.5 M Ca(OAc)2, 16% PEG 3350, 0.1 M Tris-HCl pH 8.5 using the sitting-drop vapour-diffusion method. A data set diffracting to 2.0 A was collected from a single crystal at 100 K. The crystal belongs to the orthorhombic spacegroup P2(1)2(1)2(1), with unit-cell parameters a = 53.2, b = 97.3, c = 114.3 A. The structure was refined to a final free-R factor of 24.8%. The structure reveals that despite low sequence homology, M. loti NAT1 shares the common fold as reported in previous NAT structures and exhibits the same catalytic triad of residues (Cys-His-Asp) in the active site.
Holton
Simon J
SJ
Department of Biochemistry, Oxford University, Oxford OX1 3QU, England.
Dairou
Julien
J
Sandy
James
J
Rodrigues-Lima
Fernando
F
Dupret
Jean Marie
JM
Noble
Martin E M
ME
Sim
Edith
E
D020561:Alphaproteobacteria / Q000201:enzymology*; D000595:Amino Acid Sequence; D001191:Arylamine N-Acetyltransferase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D001665:Binding Sites; D003001:Cloning, Molecular; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification
D011994:Recombinant Proteins; D001191:Arylamine N-Acetyltransferase