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| | {{STRUCTURE_2pwy| PDB=2pwy | SCENE= }} | | {{STRUCTURE_2pwy| PDB=2pwy | SCENE= }} |
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| - | '''Crystal Structure of a m1A58 tRNA methyltransferase'''
| + | ===Crystal Structure of a m1A58 tRNA methyltransferase=== |
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| - | ==Overview==
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| - | Methyltransferases from the m(1)A(58) tRNA methyltransferase (TrmI) family catalyze the S-adenosyl-l-methionine-dependent N(1)-methylation of tRNA adenosine 58. The crystal structure of Thermus thermophilus TrmI, in complex with S-adenosyl-l-homocysteine, was determined at 1.7 A resolution. This structure is closely related to that of Mycobacterium tuberculosis TrmI, and their comparison enabled us to enlighten two grooves in the TrmI structure that are large enough and electrostatically compatible to accommodate one tRNA per face of TrmI tetramer. We have then conducted a biophysical study based on electrospray ionization mass spectrometry, site-directed mutagenesis, and molecular docking. First, we confirmed the tetrameric oligomerization state of TrmI, and we showed that this protein remains tetrameric upon tRNA binding, with formation of complexes involving one to two molecules of tRNA per TrmI tetramer. Second, three key residues for the methylation reaction were identified: the universally conserved D170 and two conserved aromatic residues Y78 and Y194. We then used molecular docking to position a N(9)-methyladenine in the active site of TrmI. The N(9)-methyladenine snugly fits into the catalytic cleft, where the side chain of D170 acts as a bidentate ligand binding the amino moiety of S-adenosyl-l-methionine and the exocyclic amino group of the adenosine. Y194 interacts with the N(9)-methyladenine ring, whereas Y78 can stabilize the sugar ring. From our results, we propose that the conserved residues that form the catalytic cavity (D170, Y78, and Y194) are essential for fashioning an optimized shape of the catalytic pocket.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_18262540}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 18262540 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_18262540}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Trmi]] | | [[Category: Trmi]] |
| | [[Category: Trna-m1a58]] | | [[Category: Trna-m1a58]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 13:56:16 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 02:38:46 2008'' |
Revision as of 23:38, 28 July 2008
Template:STRUCTURE 2pwy
Crystal Structure of a m1A58 tRNA methyltransferase
Template:ABSTRACT PUBMED 18262540
About this Structure
2PWY is a Single protein structure of sequence from Thermus thermophilus. Full crystallographic information is available from OCA.
Reference
Crystal Structure of Thermus thermophilus tRNA m(1)A(58) Methyltransferase and Biophysical Characterization of Its Interaction with tRNA., Barraud P, Golinelli-Pimpaneau B, Atmanene C, Sanglier S, Van Dorsselaer A, Droogmans L, Dardel F, Tisne C, J Mol Biol. 2008 Jan 26;. PMID:18262540
Page seeded by OCA on Tue Jul 29 02:38:46 2008
