1q7m: Difference between revisions
New page: left|200px<br /><applet load="1q7m" size="450" color="white" frame="true" align="right" spinBox="true" caption="1q7m, resolution 2.10Å" /> '''Cobalamin-dependent ... |
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[[Image:1q7m.jpg|left|200px]]<br /><applet load="1q7m" size=" | [[Image:1q7m.jpg|left|200px]]<br /><applet load="1q7m" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1q7m, resolution 2.10Å" /> | caption="1q7m, resolution 2.10Å" /> | ||
'''Cobalamin-dependent methionine synthase (MetH) from Thermotoga maritima (Oxidized, Monoclinic)'''<br /> | '''Cobalamin-dependent methionine synthase (MetH) from Thermotoga maritima (Oxidized, Monoclinic)'''<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== | ||
1Q7M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima]. 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:// | 1Q7M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima]. 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=1Q7M 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: cobalamin]] | [[Category: cobalamin]] | ||
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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 14:36:46 2008'' | ||
Revision as of 15:36, 21 February 2008
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Cobalamin-dependent methionine synthase (MetH) from Thermotoga maritima (Oxidized, Monoclinic)
OverviewOverview
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 StructureAbout this Structure
1Q7M is a Single protein structure of sequence from Thermotoga maritima. Active as Methionine synthase, with EC number 2.1.1.13 Full crystallographic information is available from OCA.
ReferenceReference
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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