Structure of the yeast tRNA m7G methylation complex.
Loss of N7-methylguanosine (m7G) modification is involved in the recently discovered rapid tRNA degradation pathway. In yeast, this modification is catalyzed by the heterodimeric complex composed of a catalytic subunit Trm8 and a noncatalytic subunit Trm82. We have solved the crystal structure of Trm8 alone and in complex with Trm82. Trm8 undergoes subtle conformational changes upon Trm82 binding which explains the requirement of Trm82 for activity. Cocrystallization with the S-adenosyl-methionine methyl donor defines the putative catalytic site and a guanine binding pocket. Small-angle X-ray scattering in solution of the Trm8-Trm82 heterodimer in complex with tRNA(Phe) has enabled us to propose a low-resolution structure of the ternary complex which defines the tRNA binding mode of Trm8-Trm82 and the structural elements contributing to specificity.
Leulliot
Nicolas
N
Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR8619, Bât 430, Université de Paris-Sud, IFR115, Orsay Cedex, France. nicolas.leulliot@u-psud.fr
Chaillet
Maxime
M
Durand
Dominique
D
Ulryck
Nathalie
N
Blondeau
Karine
K
van Tilbeurgh
Herman
H
D001665:Binding Sites; D018360:Crystallography, X-Ray; D006151:Guanosine / Q000031:analogs & derivatives; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D012331:RNA, Fungal / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D012360:RNA, Transfer, Phe / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000235:genetics; D014961:X-Ray Diffraction
C116616:8-methylguanosine; D012331:RNA, Fungal; D012360:RNA, Transfer, Phe; D006151:Guanosine