1ri4: Difference between revisions
New page: left|200px<br /><applet load="1ri4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ri4, resolution 2.40Å" /> '''Structure and mechan... |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1ri4.jpg|left|200px]]<br /><applet load="1ri4" size=" | [[Image:1ri4.jpg|left|200px]]<br /><applet load="1ri4" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1ri4, resolution 2.40Å" /> | caption="1ri4, resolution 2.40Å" /> | ||
'''Structure and mechanism of mRNA cap (guanine N-7) methyltransferase'''<br /> | '''Structure and mechanism of mRNA cap (guanine N-7) methyltransferase'''<br /> | ||
==Overview== | ==Overview== | ||
A suite of crystal structures is reported for a cellular mRNA cap | A suite of crystal structures is reported for a cellular mRNA cap (guanine-N7) methyltransferase in complex with AdoMet, AdoHcy, and the cap guanylate. Superposition of ligand complexes suggests an in-line mechanism of methyl transfer, albeit without direct contacts between the enzyme and either the N7 atom of guanine (the attacking nucleophile), the methyl carbon of AdoMet, or the sulfur of AdoMet/AdoHcy (the leaving group). The structures indicate that catalysis of cap N7 methylation is accomplished by optimizing proximity and orientation of the substrates, assisted by a favorable electrostatic environment. The enzyme-ligand structures, together with new mutational data, fully account for the biochemical specificity of the cap guanine-N7 methylation reaction, an essential and defining step of eukaryotic mRNA synthesis. | ||
==About this Structure== | ==About this Structure== | ||
1RI4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Encephalitozoon_cuniculi Encephalitozoon cuniculi] with SAM as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | 1RI4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Encephalitozoon_cuniculi Encephalitozoon cuniculi] with <scene name='pdbligand=SAM:'>SAM</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RI4 OCA]. | ||
==Reference== | ==Reference== | ||
| Line 15: | Line 15: | ||
[[Category: Fabrega, C.]] | [[Category: Fabrega, C.]] | ||
[[Category: Hausmann, S.]] | [[Category: Hausmann, S.]] | ||
[[Category: Lima, C | [[Category: Lima, C D.]] | ||
[[Category: Shen, V.]] | [[Category: Shen, V.]] | ||
[[Category: Shuman, S.]] | [[Category: Shuman, S.]] | ||
| Line 25: | Line 25: | ||
[[Category: rna]] | [[Category: rna]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:51:15 2008'' | ||
Revision as of 15:51, 21 February 2008
|
Structure and mechanism of mRNA cap (guanine N-7) methyltransferase
OverviewOverview
A suite of crystal structures is reported for a cellular mRNA cap (guanine-N7) methyltransferase in complex with AdoMet, AdoHcy, and the cap guanylate. Superposition of ligand complexes suggests an in-line mechanism of methyl transfer, albeit without direct contacts between the enzyme and either the N7 atom of guanine (the attacking nucleophile), the methyl carbon of AdoMet, or the sulfur of AdoMet/AdoHcy (the leaving group). The structures indicate that catalysis of cap N7 methylation is accomplished by optimizing proximity and orientation of the substrates, assisted by a favorable electrostatic environment. The enzyme-ligand structures, together with new mutational data, fully account for the biochemical specificity of the cap guanine-N7 methylation reaction, an essential and defining step of eukaryotic mRNA synthesis.
About this StructureAbout this Structure
1RI4 is a Single protein structure of sequence from Encephalitozoon cuniculi with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Structure and mechanism of mRNA cap (guanine-N7) methyltransferase., Fabrega C, Hausmann S, Shen V, Shuman S, Lima CD, Mol Cell. 2004 Jan 16;13(1):77-89. PMID:14731396
Page seeded by OCA on Thu Feb 21 14:51:15 2008