8g3h: Difference between revisions

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-'''Unreleased structure'''
-The entry 8g3h is ON HOLD
+==Structure of cobalamin-dependent methionine synthase (MetH) in a resting state==
+<StructureSection load='8g3h' size='340' side='right'caption='[[8g3h]], [[Resolution|resolution]] 3.60&Aring;' scene=''>
+== Structural highlights ==
+<table><tr><td colspan='2'>[[8g3h]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_filiformis Thermus filiformis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8G3H OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8G3H FirstGlance]. <br>
+</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.6&#8491;</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=B12:COBALAMIN'>B12</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=8g3h FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8g3h OCA], [https://pdbe.org/8g3h PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8g3h RCSB], [https://www.ebi.ac.uk/pdbsum/8g3h PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8g3h ProSAT]</span></td></tr>
+</table>
+== Function ==
+[https://www.uniprot.org/uniprot/A0A0A2XCD7_THEFI A0A0A2XCD7_THEFI] Catalyzes the transfer of a methyl group from methyl-cobalamin to homocysteine, yielding enzyme-bound cob(I)alamin and methionine. Subsequently, remethylates the cofactor using methyltetrahydrofolate.[ARBA:ARBA00025552][PIRNR:PIRNR000381]
+<div style="background-color:#fffaf0;">
+== Publication Abstract from PubMed ==
+Cobalamin-dependent methionine synthase (MetH) catalyzes the synthesis of methionine from homocysteine and 5-methyltetrahydrofolate (CH(3)-H(4)folate) using the unique chemistry of its cofactor. In doing so, MetH links the cycling of S-adenosylmethionine with the folate cycle in one-carbon metabolism. Extensive biochemical and structural studies on Escherichia coli MetH have shown that this flexible, multidomain enzyme adopts two major conformations to prevent a futile cycle of methionine production and consumption. However, as MetH is highly dynamic as well as both a photosensitive and oxygen-sensitive metalloenzyme, it poses special challenges for structural studies, and existing structures have necessarily come from a "divide and conquer" approach. In this study, we investigate E. coli MetH and a thermophilic homolog from Thermus filiformis using small-angle X-ray scattering (SAXS), single-particle cryoelectron microscopy (cryo-EM), and extensive analysis of the AlphaFold2 database to present a structural description of the full-length MetH in its entirety. Using SAXS, we describe a common resting-state conformation shared by both active and inactive oxidation states of MetH and the roles of CH(3)-H(4)folate and flavodoxin in initiating turnover and reactivation. By combining SAXS with a 3.6-A cryo-EM structure of the T. filiformis MetH, we show that the resting-state conformation consists of a stable arrangement of the catalytic domains that is linked to a highly mobile reactivation domain. Finally, by combining AlphaFold2-guided sequence analysis and our experimental findings, we propose a general model for functional switching in MetH.
-Authors:
+Conformational switching and flexibility in cobalamin-dependent methionine synthase studied by small-angle X-ray scattering and cryoelectron microscopy.,Watkins MB, Wang H, Burnim A, Ando N Proc Natl Acad Sci U S A. 2023 Jun 27;120(26):e2302531120. doi: , 10.1073/pnas.2302531120. Epub 2023 Jun 20. PMID:37339208<ref>PMID:37339208</ref>
-Description:
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
-[[Category: Unreleased Structures]]
+</div>
+<div class="pdbe-citations 8g3h" style="background-color:#fffaf0;"></div>
+== References ==
+<references/>
+__TOC__
+</StructureSection>
+[[Category: Large Structures]]
+[[Category: Thermus filiformis]]
+[[Category: Ando N]]
+[[Category: Watkins MB]]