View source for 7r3a


==Crystal structure of S-adenosyl-L-homocysteine hydrolase from Methanococcus maripaludis in complex with inosine==
<StructureSection load='7r3a' size='340' side='right'caption='[[7r3a]], [[Resolution|resolution]] 2.53&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7r3a]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Methanococcus_maripaludis Methanococcus maripaludis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7R3A OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7R3A FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.53&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</scene>, <scene name='pdbligand=NOS:INOSINE'>NOS</scene>, <scene name='pdbligand=PG4:TETRAETHYLENE+GLYCOL'>PG4</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=7r3a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7r3a OCA], [https://pdbe.org/7r3a PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7r3a RCSB], [https://www.ebi.ac.uk/pdbsum/7r3a PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7r3a ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SIHH_METMP SIHH_METMP] Catalyzes the hydrolysis of S-inosyl-L-homocysteine (SIH) to L-homocysteine (Hcy) and inosine. Likely functions in a S-adenosyl-L-methionine (SAM) recycling pathway from S-adenosyl-L-homocysteine (SAH) produced from SAM-dependent methylation reactions. Can also catalyze the reverse reaction in vitro, i.e. the synthesis of SIH from Hcy and inosine.[HAMAP-Rule:MF_00563]
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== Publication Abstract from PubMed ==
S-Adenosyl-L-homocysteine hydrolase (SAHH) reversibly cleaves S-adenosyl-L-homocysteine, the product of S-adenosyl-L-methionine-dependent methylation reactions. The conversion of S-adenosyl-L-homocysteine into adenosine and L-homocysteine plays an important role in the regulation of the methyl cycle. An alternative metabolic route for S-adenosyl-L-methionine regeneration in the extremophiles Methanocaldococcus jannaschii and Thermotoga maritima has been identified, featuring the deamination of S-adenosyl-L-homocysteine to S-inosyl-L-homocysteine. Herein, we report the structural characterisation of different archaeal SAHHs together with a biochemical analysis of various SAHHs from all three domains of life. Homologues deriving from the Euryarchaeota phylum show a higher conversion rate with S-inosyl-L-homocysteine compared to S-adenosyl-L-homocysteine. Crystal structures of SAHH originating from Pyrococcus furiosus in complex with SLH and inosine as ligands, show architectural flexibility in the active site and offer deeper insights into the binding mode of hypoxanthine-containing substrates. Altogether, the findings of our study support the understanding of an alternative metabolic route for S-adenosyl-L-methionine and offer insights into the evolutionary progression and diversification of SAHHs involved in methyl and purine salvage pathways.

Structure, function and substrate preferences of archaeal S-adenosyl-L-homocysteine hydrolases.,Koeppl LH, Popadic D, Saleem-Batcha R, Germer P, Andexer JN Commun Biol. 2024 Mar 29;7(1):380. doi: 10.1038/s42003-024-06078-9. PMID:38548921<ref>PMID:38548921</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 7r3a" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Methanococcus maripaludis]]
[[Category: Andexer JN]]
[[Category: Popadic D]]
[[Category: Saleem-Batcha R]]