title: Structure of a class II TrmH tRNA-modifying enzyme from Aquifex aeolicus.
abstract: Biological RNAs contain a variety of post-transcriptional modifications that facilitate their efficient function in the cellular environment. One of the two most common forms of modification is methylation of the 2'-hydroxyl group of the ribose sugar, which is performed by a number of S-adenosylmethionine (SAM) dependent methyltransferases. In bacteria, many of these modifications in tRNA and rRNA are carried out by the alpha/beta-knot superfamily of enzymes, whose SAM-binding pocket is created by a characteristic deep trefoil knot. TrmH, an enzyme found throughout all three kingdoms of life, modifies the universally conserved guanosine 18 position of tRNA. The crystal structure of TrmH from the thermophilic bacterium Aquifex aeolicus has been determined at 1.85 A resolution using data collected from a synchrotron-radiation source. The protein reveals a fold typical of members of the SpoU clan of proteins, a subfamily of the alpha/beta-knot superfamily, with alpha-helical extensions at the N- and C-termini that are likely to be involved in tRNA binding.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Campus Box 215, Boulder, CO 80309-0215, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Pleshe
authors.forename: John
authors.initials: J
authors.lastname: Truesdell
authors.forename: Robert T
authors.initials: RT
authors.lastname: Batey
mesh_terms: D001419:Bacteria / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification; D001665:Binding Sites; D003460:Crystallization; D017433:Protein Structure, Secondary; D016601:RNA-Binding Proteins / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism; D055672:Static Electricity
chemical_list: D001426:Bacterial Proteins; D016601:RNA-Binding Proteins; D012436:S-Adenosylmethionine