View source for 5bro


==Crystal structure of modified HexB (modB)==
<StructureSection load='5bro' size='340' side='right'caption='[[5bro]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5bro]] is a 1 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=5BRO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5BRO 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]] 2.4&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FMT:FORMIC+ACID'>FMT</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</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=5bro FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5bro OCA], [https://pdbe.org/5bro PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5bro RCSB], [https://www.ebi.ac.uk/pdbsum/5bro PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5bro ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/HEXB_HUMAN HEXB_HUMAN] Defects in HEXB are the cause of GM2-gangliosidosis type 2 (GM2G2) [MIM:[https://omim.org/entry/268800 268800]; also known as Sandhoff disease. GM2-gangliosidosis is an autosomal recessive lysosomal storage disease marked by the accumulation of GM2 gangliosides in the neuronal cells. GM2G2 is clinically indistinguishable from GM2-gangliosidosis type 1, presenting startle reactions, early blindness, progressive motor and mental deterioration, macrocephaly and cherry-red spots on the macula.<ref>PMID:1720305</ref> <ref>PMID:1531140</ref> <ref>PMID:8357844</ref> <ref>PMID:7626071</ref> <ref>PMID:7557963</ref> <ref>PMID:7633435</ref> <ref>PMID:8950198</ref> <ref>PMID:9401004</ref> <ref>PMID:9856491</ref> <ref>PMID:9694901</ref> 
== Function ==
[https://www.uniprot.org/uniprot/HEXB_HUMAN HEXB_HUMAN] Responsible for the degradation of GM2 gangliosides, and a variety of other molecules containing terminal N-acetyl hexosamines, in the brain and other tissues.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
GM2 gangliosidoses, including Tay-Sachs and Sandhoff diseases, are neurodegenerative lysosomal storage diseases that are caused by deficiency of beta-hexosaminidase A, which comprises an alphabeta heterodimer. There are no effective treatments for these diseases; however, various strategies aimed at restoring beta-hexosaminidase A have been explored. Here, we produced a modified human hexosaminidase subunit beta (HexB), which we have termed mod2B, composed of homodimeric beta subunits that contain amino acid sequences from the alpha subunit that confer GM2 ganglioside-degrading activity and protease resistance. We also developed fluorescent probes that allow visualization of endocytosis of mod2B via mannose 6-phosphate receptors and delivery of mod2B to lysosomes in GM2 gangliosidosis models. In addition, we applied imaging mass spectrometry to monitor efficacy of this approach in Sandhoff disease model mice. Following i.c.v. administration, mod2B was widely distributed and reduced accumulation of GM2, asialo-GM2, and bis(monoacylglycero)phosphate in brain regions including the hypothalamus, hippocampus, and cerebellum. Moreover, mod2B administration markedly improved motor dysfunction and a prolonged lifespan in Sandhoff disease mice. Together, the results of our study indicate that mod2B has potential for intracerebrospinal fluid enzyme replacement therapy and should be further explored as a gene therapy for GM2 gangliosidoses.

Protease-resistant modified human beta-hexosaminidase B ameliorates symptoms in GM2 gangliosidosis model.,Kitakaze K, Mizutani Y, Sugiyama E, Tasaki C, Tsuji D, Maita N, Hirokawa T, Asanuma D, Kamiya M, Sato K, Setou M, Urano Y, Togawa T, Otaka A, Sakuraba H, Itoh K J Clin Invest. 2016 May 2;126(5):1691-703. doi: 10.1172/JCI85300. Epub 2016 Mar, 28. PMID:27018595<ref>PMID:27018595</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5bro" style="background-color:#fffaf0;"></div>

==See Also==
*[[Beta-Hexosaminidase|Beta-Hexosaminidase]]
*[[Beta-Hexosaminidase 3D structures|Beta-Hexosaminidase 3D structures]]
*[[Beta-N-acetylhexosaminidase 3D structures|Beta-N-acetylhexosaminidase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Itoh K]]
[[Category: Kitakaze K]]
[[Category: Maita N]]