User:Kia Yang/sandbox

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This page is being worked on during the Spring 2022 semester.
This page is being worked on during the Spring 2022 semester.
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==Function==
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Methionine is an essential amino acid required by our bodies for healthy cell and tissue growth. Methionine is not naturally derived, and is obtained from our diet in the form of homocysteine. '''Methionine synthase''' (abbrev. MS; EC: 2.1.1.13), a B12-dependent enzyme, is a critical part of the one-carbon metabolism cycle. It catalyzes the methylation of homocysteine to methionine. MS mutations and B-12 deficiencies are associated with serious health conditions such as birth abnormalities and anemia.
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Methionine is an essential amino acid required by our bodies for healthy cell and tissue growth. It is essential because is not naturally derived, and must be obtained from our diet first in the form of homocysteine. Methionine synthase (abbrev. MS; EC: 2.1.1.13), a B12-dependent enzyme, is a critical part of the one-carbon metabolism cycle because it converts homocysteine to methionine.
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==Function==
[[Image:Overall.jpeg]]
[[Image:Overall.jpeg]]
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== Relevance ==
== Relevance ==
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Methionine deficiency can result in diseases such as birth abnormalities<ref name="Kung et al"/>.
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MS mutations and B-12 deficiencies can result in diseases<ref name="Kung et al"/>.
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<StructureSection load='1k7y' size='310' side='right' caption='B12 dependent fragment of E. coli methionine synthase with Cobalt (in pink)' scene=''>
 
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== Structural highlights ==
 
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The full structure of MS has yet to be determined but studies have found it contains <scene name='90/907471/Superposition_1/2'>4 domains</scene>, each domain with a unique function that bind to Cob(I)alamin as the methyl carrier (in pink), methyltetrahydrofolate as the methyl donor in the catalytic cycle (in blue), Homocysteine as the methyl acceptor (in yellow), and S-adenosyl-L-methionine or SAM (in red) as the methyl donor in the reactivation cycle<ref name="Bandarian et al">DOI: 10.1038/nsb738</ref>. During each cycle, the domains must be positioned close enough to the Cobalamin in order for methyl transfer to be successful.
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== Structural highlights ==
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<StructureSection load='1k7y' size='310' side='right' caption='B12 dependent fragment of E. coli methionine synthase with Cobalt (in pink)' scene=''>
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The full structure of MS has yet to be determined but studies have found it contains <scene name='90/907471/Superposition_1/2'>4 domains</scene>, each domain with a unique function that bind to Cob(I)alamin as the methyl carrier (in pink), methyltetrahydrofolate as the methyl donor in the catalytic cycle (in blue), Homocysteine as the methyl acceptor (in yellow), and S-adenosylmethionine or SAM (in red) as the methyl donor in the reactivation cycle<ref name="Bandarian et al">DOI: 10.1038/nsb738</ref>. During each cycle, the domains must be positioned close enough to the Cobalamin in order for methyl transfer to be successful.
== Vitamin B12 ==
== Vitamin B12 ==

Revision as of 15:12, 13 April 2022

This page is being worked on during the Spring 2022 semester.

Methionine is an essential amino acid required by our bodies for healthy cell and tissue growth. Methionine is not naturally derived, and is obtained from our diet in the form of homocysteine. Methionine synthase (abbrev. MS; EC: 2.1.1.13), a B12-dependent enzyme, is a critical part of the one-carbon metabolism cycle. It catalyzes the methylation of homocysteine to methionine. MS mutations and B-12 deficiencies are associated with serious health conditions such as birth abnormalities and anemia.


Contents

Function

Image:Overall.jpeg

The change from homocysteine to methionine is an SN2 reaction, as seen above, where the methyl group on N-5 from methyltetrahydrofolate (MTHF), is donated. MTHF is a product of Methylenetetrahydrofolate reductase (MTHFR) from the folate cycle [link Shaylie's page here]. This is a complex reaction as tetrahydrofolate, the product, is a poor leaving group and thus requiring a "super nucleophile", vitamin B12 cob(I)alamin, to carry out the reaction[1]; the methyl carrier.

Relevance

MS mutations and B-12 deficiencies can result in diseases[1].


Structural highlights

B12 dependent fragment of E. coli methionine synthase with Cobalt (in pink)

Drag the structure with the mouse to rotate

References

[3]

  1. ↑ 1.0 1.1 Kung Y, Ando N, Doukov TI, Blasiak LC, Bender G, Seravalli J, Ragsdale SW, Drennan CL. Visualizing molecular juggling within a B(12)-dependent methyltransferase complex. Nature. 2012 Mar 14. doi: 10.1038/nature10916. PMID:22419154 doi:10.1038/nature10916
  2. ↑ 2.0 2.1 Bandarian V, Pattridge KA, Lennon BW, Huddler DP, Matthews RG, Ludwig ML. Domain alternation switches B(12)-dependent methionine synthase to the activation conformation. Nat Struct Biol. 2002 Jan;9(1):53-6. PMID:11731805 doi:10.1038/nsb738
  3. ↑ Barra L, Fontenelle C, Ermel G, Trautwetter A, Walker GC, Blanco C. Interrelations between glycine betaine catabolism and methionine biosynthesis in Sinorhizobium meliloti strain 102F34. J Bacteriol. 2006 Oct;188(20):7195-204. doi: 10.1128/JB.00208-06. PMID:17015658 doi:http://dx.doi.org/10.1128/JB.00208-06

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Kia Yang

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