View source for 4l3v


==Crystal structure of delta516-525 human cystathionine beta-synthase==
<StructureSection load='4l3v' size='340' side='right'caption='[[4l3v]], [[Resolution|resolution]] 3.63&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4l3v]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4L3V OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4L3V 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]] 3.628&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=PLP:PYRIDOXAL-5-PHOSPHATE'>PLP</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=4l3v FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4l3v OCA], [https://pdbe.org/4l3v PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4l3v RCSB], [https://www.ebi.ac.uk/pdbsum/4l3v PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4l3v ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/CBS_HUMAN CBS_HUMAN] Defects in CBS are the cause of cystathionine beta-synthase deficiency (CBSD) [MIM:[https://omim.org/entry/236200 236200]. CBSD is an enzymatic deficiency resulting in altered sulfur metabolism and homocystinuria. The clinical features of untreated homocystinuria due to CBS deficiency include myopia, ectopia lentis, mental retardation, skeletal anomalies resembling Marfan syndrome, and thromboembolic events. Light skin and hair can also be present. Biochemical features include increased urinary homocystine and methionine.<ref>PMID:1301198</ref> <ref>PMID:8353501</ref> <ref>PMID:7506602</ref> <ref>PMID:7981678</ref> <ref>PMID:7849717</ref> <ref>PMID:7967489</ref> <ref>PMID:7611293</ref> <ref>PMID:7762555</ref> <ref>PMID:7635485</ref> <ref>PMID:8528202</ref> <ref>PMID:7564249</ref> <ref>PMID:8755636</ref> <ref>PMID:8803779</ref> <ref>PMID:9156316</ref> <ref>PMID:9361025</ref> <ref>PMID:8990018</ref> <ref>PMID:9266356</ref> <ref>PMID:10462600</ref> <ref>PMID:10215408</ref> <ref>PMID:9889017</ref> <ref>PMID:10408774</ref> <ref>PMID:11013450</ref> <ref>PMID:11359213</ref> <ref>PMID:11553052</ref> <ref>PMID:12007221</ref> <ref>PMID:12124992</ref> <ref>PMID:12815602</ref> <ref>PMID:14635102</ref> <ref>PMID:15146473</ref> <ref>PMID:15365998</ref> <ref>PMID:15993874</ref> <ref>PMID:16205833</ref> <ref>PMID:16429402</ref> <ref>PMID:21520339</ref> <ref>PMID:21240075</ref> 
== Function ==
[https://www.uniprot.org/uniprot/CBS_HUMAN CBS_HUMAN] Only known pyridoxal phosphate-dependent enzyme that contains heme. Important regulator of hydrogen sulfide, especially in the brain, utilizing cysteine instead of serine to catalyze the formation of hydrogen sulfide. Hydrogen sulfide is a gastratransmitter with signaling and cytoprotective effects such as acting as a neuromodulator in the brain to protect neurons against hypoxic injury (By similarity).
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Cystathionine beta-synthase (CBS) controls the flux of sulfur from methionine to cysteine, a precursor of glutathione, taurine, and H2S. CBS condenses serine and homocysteine to cystathionine with the help of three cofactors, heme, pyridoxal-5'-phosphate, and S-adenosyl-l-methionine. Inherited deficiency of CBS activity causes homocystinuria, the most frequent disorder of sulfur metabolism. We present the structure of the human enzyme, discuss the unique arrangement of the CBS domains in the C-terminal region, and propose how they interact with the catalytic core of the complementary subunit to regulate access to the catalytic site. This arrangement clearly contrasts with other proteins containing the CBS domain including the recent Drosophila melanogaster CBS structure. The absence of large conformational changes and the crystal structure of the partially activated pathogenic D444N mutant suggest that the rotation of CBS motifs and relaxation of loops delineating the entrance to the catalytic site represent the most likely molecular mechanism of CBS activation by S-adenosyl-l-methionine. Moreover, our data suggest how tetramers, the native quaternary structure of the mammalian CBS enzymes, are formed. Because of its central role in transsulfuration, redox status, and H2S biogenesis, CBS represents a very attractive therapeutic target. The availability of the structure will help us understand the pathogenicity of the numerous missense mutations causing inherited homocystinuria and will allow the rational design of compounds modulating CBS activity.

Structural basis of regulation and oligomerization of human cystathionine beta-synthase, the central enzyme of transsulfuration.,Ereno-Orbea J, Majtan T, Oyenarte I, Kraus JP, Martinez-Cruz LA Proc Natl Acad Sci U S A. 2013 Sep 16. PMID:24043838<ref>PMID:24043838</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4l3v" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cystathionine ÃÂ²-synthase 3D structures|Cystathionine ÃÂ²-synthase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Ereno J]]
[[Category: Kraus JP]]
[[Category: Majtan T]]
[[Category: Martinez LA]]
[[Category: Oyenarte I]]