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| {{STRUCTURE_1k7y| PDB=1k7y | SCENE= }} | | {{STRUCTURE_1k7y| PDB=1k7y | SCENE= }} |
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| '''E. coli MetH C-terminal fragment (649-1227)'''
| | ===E. coli MetH C-terminal fragment (649-1227)=== |
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| ==Overview==
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| B(12)-dependent methionine synthase (MetH) from Escherichia coli is a large modular protein that uses bound cobalamin as an intermediate methyl carrier. Major domain rearrangements have been postulated to explain how cobalamin reacts with three different substrates: homocysteine, methyltetrahydrofolate and S-adenosylmethionine (AdoMet). Here we describe the 3.0 A structure of a 65 kDa C-terminal fragment of MetH that spans the cobalamin- and AdoMet-binding domains, arranged in a conformation suitable for the methyl transfer from AdoMet to cobalamin that occurs during activation. In the conversion to the activation conformation, a helical domain that capped the cofactor moves 26 A and rotates by 63 degrees, allowing formation of a new interface between cobalamin and the AdoMet-binding (activation) domain. Interactions with the MetH activation domain drive the cobalamin away from its binding domain in a way that requires dissociation of the axial cobalt ligand and, thereby, provide a mechanism for control of the distribution of enzyme conformations.
| | The line below this paragraph, {{ABSTRACT_PUBMED_11731805}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 11731805 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_11731805}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Domain interaction]] | | [[Category: Domain interaction]] |
| [[Category: Motion of 4-helix bundle]] | | [[Category: Motion of 4-helix bundle]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:24:54 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jul 2 09:55:16 2008'' |