1q85
From Proteopedia
(New page: 200px<br /><applet load="1q85" size="450" color="white" frame="true" align="right" spinBox="true" caption="1q85, resolution 2.0Å" /> '''Cobalamin-dependent m...) |
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| - | [[Image:1q85.gif|left|200px]]<br /><applet load="1q85" size=" | + | [[Image:1q85.gif|left|200px]]<br /><applet load="1q85" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1q85, resolution 2.0Å" /> | caption="1q85, resolution 2.0Å" /> | ||
'''Cobalamin-dependent methionine synthase (1-566) from Thermotoga maritima (Cd2+ complex, Se-Met)'''<br /> | '''Cobalamin-dependent methionine synthase (1-566) from Thermotoga maritima (Cd2+ complex, Se-Met)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | B(12)-dependent methionine synthase (MetH) is a large modular enzyme that | + | B(12)-dependent methionine synthase (MetH) is a large modular enzyme that utilizes the cobalamin cofactor as a methyl donor or acceptor in three separate reactions. Each methyl transfer occurs at a different substrate-binding domain and requires a different arrangement of modules. In the catalytic cycle, the cobalamin-binding domain carries methylcobalamin to the homocysteine (Hcy) domain to form methionine and returns cob(I)alamin to the folate (Fol) domain for remethylation by methyltetrahydrofolate (CH(3)-H(4)folate). Here, we describe crystal structures of a fragment of MetH from Thermotoga maritima comprising the domains that bind Hcy and CH(3)-H(4)folate. These substrate-binding domains are (beta alpha)(8) barrels packed tightly against one another with their barrel axes perpendicular. The properties of the domain interface suggest that the two barrels remain associated during catalysis. The Hcy and CH(3)-H(4)folate substrates are bound at the C termini of their respective barrels in orientations that position them for reaction with cobalamin, but the two active sites are separated by approximately 50 A. To complete the catalytic cycle, the cobalamin-binding domain must travel back and forth between these distant active sites. |
==About this Structure== | ==About this Structure== | ||
| - | 1Q85 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima] with CD as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Methionine_synthase Methionine synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.13 2.1.1.13] Full crystallographic information is available from [http:// | + | 1Q85 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima] with <scene name='pdbligand=CD:'>CD</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Methionine_synthase Methionine synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.13 2.1.1.13] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Q85 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Thermotoga maritima]] | [[Category: Thermotoga maritima]] | ||
| - | [[Category: Evans, J | + | [[Category: Evans, J C.]] |
| - | [[Category: Hilgers, M | + | [[Category: Hilgers, M T.]] |
| - | [[Category: Huddler, D | + | [[Category: Huddler, D P.]] |
| - | [[Category: Ludwig, M | + | [[Category: Ludwig, M L.]] |
| - | [[Category: Matthews, R | + | [[Category: Matthews, R G.]] |
[[Category: Romanchuk, G.]] | [[Category: Romanchuk, G.]] | ||
[[Category: CD]] | [[Category: CD]] | ||
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[[Category: vitamin b12]] | [[Category: vitamin b12]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:36:50 2008'' |
Revision as of 12:36, 21 February 2008
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Cobalamin-dependent methionine synthase (1-566) from Thermotoga maritima (Cd2+ complex, Se-Met)
Overview
B(12)-dependent methionine synthase (MetH) is a large modular enzyme that utilizes the cobalamin cofactor as a methyl donor or acceptor in three separate reactions. Each methyl transfer occurs at a different substrate-binding domain and requires a different arrangement of modules. In the catalytic cycle, the cobalamin-binding domain carries methylcobalamin to the homocysteine (Hcy) domain to form methionine and returns cob(I)alamin to the folate (Fol) domain for remethylation by methyltetrahydrofolate (CH(3)-H(4)folate). Here, we describe crystal structures of a fragment of MetH from Thermotoga maritima comprising the domains that bind Hcy and CH(3)-H(4)folate. These substrate-binding domains are (beta alpha)(8) barrels packed tightly against one another with their barrel axes perpendicular. The properties of the domain interface suggest that the two barrels remain associated during catalysis. The Hcy and CH(3)-H(4)folate substrates are bound at the C termini of their respective barrels in orientations that position them for reaction with cobalamin, but the two active sites are separated by approximately 50 A. To complete the catalytic cycle, the cobalamin-binding domain must travel back and forth between these distant active sites.
About this Structure
1Q85 is a Single protein structure of sequence from Thermotoga maritima with as ligand. Active as Methionine synthase, with EC number 2.1.1.13 Full crystallographic information is available from OCA.
Reference
Structures of the N-terminal modules imply large domain motions during catalysis by methionine synthase., Evans JC, Huddler DP, Hilgers MT, Romanchuk G, Matthews RG, Ludwig ML, Proc Natl Acad Sci U S A. 2004 Mar 16;101(11):3729-36. Epub 2004 Jan 29. PMID:14752199
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