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[[Image:1xwf.gif|left|200px]]<br /><applet load="1xwf" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1xwf, resolution 2.8&Aring;" />
'''K185N mutated S-adenosylhomocysteine hydrolase'''<br />


==Overview==
==K185N mutated S-adenosylhomocysteine hydrolase==
S-adenosylhomocysteine hydrolase (AdoHcyase) catalyzes the hydrolysis of S-adenosylhomocysteine (AdoHcy) to form adenosine and homocysteine. The crystal structure of the K185N mutated enzyme, which has weak catalytic activity (0.1%), has been determined at 2.8 A resolution and supports the previously predicted mechanism [Takata, Y., Yamada, T., Huang, Y., Komoto, J., Gomi, T., Ogawa, H., Fujioka, M., &amp; Takusagawa, F. (2002). Catalytic mechanism of S-adenosylhomocysteine hydrolase. Site-directed mutagenesis of Asp-130, Lys-185, Asp-189, and Asn-190. J. Biol. Chem. 277, 22670-22676]. The mutated enzyme has an intermediate structure between the open and closed conformation, observed in the substrate-free enzyme and in the inhibitor complexes, respectively. H54, H300, and H352 were mutated to asparagine, respectively, to identify the roles of the histidine residues in catalysis. The kinetic data of H54N, H300N, and H354N mutated enzymes suggest that H54 is the amino acid residue that acts as a general acid/base to cleave the C5'-S(D) bond of AdoHcy. The E155Q mutated enzyme retained a large portion of the catalytic activity (31%), while the E155D mutated enzyme lost most of it (0.3%). The NADH accumulation measurements of the mutated enzymes indicated that the C3'-oxidation and the C4'-proton abstraction are a concerted event and the C5'-S(D) bond cleavage is an independent event. The C4'-proton exchange measurements indicate that the enzyme has an open conformation when AdoHcy is converted to 3'-keto-4', 5'-dehydro-Ado in the active site. With the results of this study and those of the previous studies, a detailed catalytic mechanism of AdoHcyase is described. K185 facilitates the C3'-oxidation, D130 abstracts the C4'-proton, D189, and E155 act as a communicator between the concerted C3'-oxidation and C4'-proton abstraction, and H54 plays as a general acid to cleave the C5'-S(D) bond of AdoHcy.
<StructureSection load='1xwf' size='340' side='right'caption='[[1xwf]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1xwf]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XWF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XWF 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]] 2.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ADN:ADENOSINE'>ADN</scene>, <scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</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=1xwf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xwf OCA], [https://pdbe.org/1xwf PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xwf RCSB], [https://www.ebi.ac.uk/pdbsum/1xwf PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xwf ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SAHH_RAT SAHH_RAT] Adenosylhomocysteine is a competitive inhibitor of S-adenosyl-L-methionine-dependent methyl transferase reactions; therefore adenosylhomocysteinase may play a key role in the control of methylations via regulation of the intracellular concentration of adenosylhomocysteine.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/xw/1xwf_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1xwf ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1XWF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=NAD:'>NAD</scene> and <scene name='pdbligand=ADN:'>ADN</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Adenosylhomocysteinase Adenosylhomocysteinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.3.1.1 3.3.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XWF OCA].
*[[S-adenosylhomocysteine hydrolase|S-adenosylhomocysteine hydrolase]]
 
__TOC__
==Reference==
</StructureSection>
Catalytic mechanism of S-adenosylhomocysteine hydrolase: roles of His 54, Asp130, Glu155, Lys185, and Aspl89., Yamada T, Takata Y, Komoto J, Gomi T, Ogawa H, Fujioka M, Takusagawa F, Int J Biochem Cell Biol. 2005 Nov;37(11):2417-35. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16061414 16061414]
[[Category: Large Structures]]
[[Category: Adenosylhomocysteinase]]
[[Category: Rattus norvegicus]]
[[Category: Rattus norvegicus]]
[[Category: Single protein]]
[[Category: Fujioka M]]
[[Category: Fujioka, M.]]
[[Category: Gomi T]]
[[Category: Gomi, T.]]
[[Category: Komoto J]]
[[Category: Komoto, J.]]
[[Category: Ogawa H]]
[[Category: Ogawa, H.]]
[[Category: Takata Y]]
[[Category: Takata, Y.]]
[[Category: Takusagawa F]]
[[Category: Takusagawa, F.]]
[[Category: Yamada T]]
[[Category: Yamada, T.]]
[[Category: ADN]]
[[Category: NAD]]
[[Category: adohcy hydrolase]]
[[Category: adohcyase]]
[[Category: s-adenosylhomocysteine hydrolase]]
[[Category: sahh]]
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:59:24 2008''

Latest revision as of 11:53, 14 February 2024

K185N mutated S-adenosylhomocysteine hydrolaseK185N mutated S-adenosylhomocysteine hydrolase

Structural highlights

1xwf is a 4 chain structure with sequence from Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.8Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

SAHH_RAT Adenosylhomocysteine is a competitive inhibitor of S-adenosyl-L-methionine-dependent methyl transferase reactions; therefore adenosylhomocysteinase may play a key role in the control of methylations via regulation of the intracellular concentration of adenosylhomocysteine.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

1xwf, resolution 2.80Å

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