5BRO

Crystal structure of modified HexB (modB)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.190 

wwPDB Validation   3D Report Full Report


This is version 2.0 of the entry. See complete history


Literature

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.

(2016) J Clin Invest 126: 1691-1703

  • DOI: 10.1172/JCI85300
  • Primary Citation of Related Structures:  
    5BRO

  • PubMed Abstract: 
  • GM2 gangliosidoses, including Tay-Sachs and Sandhoff diseases, are neurodegenerative lysosomal storage diseases that are caused by deficiency of β-hexosaminidase A, which comprises an αβ heterodimer. There are no effective treatments for these diseases; however, various strategies aimed at restoring β-hexosaminidase A have been explored ...

    GM2 gangliosidoses, including Tay-Sachs and Sandhoff diseases, are neurodegenerative lysosomal storage diseases that are caused by deficiency of β-hexosaminidase A, which comprises an αβ heterodimer. There are no effective treatments for these diseases; however, various strategies aimed at restoring β-hexosaminidase A have been explored. Here, we produced a modified human hexosaminidase subunit β (HexB), which we have termed mod2B, composed of homodimeric β subunits that contain amino acid sequences from the α 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.


    Related Citations: 
    • Therapeutic potential of intracerebroventricular replacement of modified human beta-hexosaminidase B for GM2 gangliosidosis.
      Matsuoka, K., Tamura, T., Tsuji, D., Dohzono, Y., Kitakaze, K., Ohno, K., Saito, S., Sakuraba, H., Itoh, K.
      (2011) Mol Ther 19: 1017

    Organizational Affiliation

    Department ofChemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Beta-hexosaminidase subunit beta A514Homo sapiensMutation(s): 6 
Gene Names: HEXBHCC7
EC: 3.2.1.52
Find proteins for P07686 (Homo sapiens)
Explore P07686 
Go to UniProtKB:  P07686
NIH Common Fund Data Resources
PHAROS:  P07686
Protein Feature View
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
B, C
2 N-Glycosylation Oligosaccharides Interaction
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download Ideal Coordinates CCD File 
A
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
FMT
Query on FMT

Download Ideal Coordinates CCD File 
A
FORMIC ACID
C H2 O2
BDAGIHXWWSANSR-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.190 
  • Space Group: P 42 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 126.47α = 90
b = 126.47β = 90
c = 88.31γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
iMOSFLMdata reduction
SCALAdata scaling
MOLREPphasing
Cootmodel building

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-05-04
    Type: Initial release
  • Version 1.1: 2020-02-19
    Changes: Data collection, Database references, Derived calculations
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary