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Open data
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Basic information
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Title | Cryo-EM structure of human HGSNAT bound with CoA | |||||||||
![]() | sharpened map | |||||||||
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![]() | Membrane protein / Lysosome / Transmembrane acetyltransferase | |||||||||
Function / homology | ![]() heparan-alpha-glucosaminide N-acetyltransferase / heparan-alpha-glucosaminide N-acetyltransferase activity / MPS IIIC - Sanfilippo syndrome C / heparan sulfate proteoglycan catabolic process / HS-GAG degradation / lysosomal transport / acyltransferase activity / protein complex oligomerization / tertiary granule membrane / specific granule membrane ...heparan-alpha-glucosaminide N-acetyltransferase / heparan-alpha-glucosaminide N-acetyltransferase activity / MPS IIIC - Sanfilippo syndrome C / heparan sulfate proteoglycan catabolic process / HS-GAG degradation / lysosomal transport / acyltransferase activity / protein complex oligomerization / tertiary granule membrane / specific granule membrane / lysosomal lumen / lysosomal membrane / Neutrophil degranulation / plasma membrane Similarity search - Function | |||||||||
Biological species | ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 3.12 Å | |||||||||
![]() | Li F / Zhao B | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural and mechanistic insights into a lysosomal membrane enzyme HGSNAT involved in Sanfilippo syndrome. Authors: Boyang Zhao / Zhongzheng Cao / Yi Zheng / Phuong Nguyen / Alisa Bowen / Robert H Edwards / Robert M Stroud / Yi Zhou / Menno Van Lookeren Campagne / Fei Li / ![]() Abstract: Heparan sulfate (HS) is degraded in lysosome by a series of glycosidases. Before the glycosidases can act, the terminal glucosamine of HS must be acetylated by the integral lysosomal membrane enzyme ...Heparan sulfate (HS) is degraded in lysosome by a series of glycosidases. Before the glycosidases can act, the terminal glucosamine of HS must be acetylated by the integral lysosomal membrane enzyme heparan-α-glucosaminide N-acetyltransferase (HGSNAT). Mutations of HGSNAT cause HS accumulation and consequently mucopolysaccharidosis IIIC, a devastating lysosomal storage disease characterized by progressive neurological deterioration and early death where no treatment is available. HGSNAT catalyzes a unique transmembrane acetylation reaction where the acetyl group of cytosolic acetyl-CoA is transported across the lysosomal membrane and attached to HS in one reaction. However, the reaction mechanism remains elusive. Here we report six cryo-EM structures of HGSNAT along the reaction pathway. These structures reveal a dimer arrangement and a unique structural fold, which enables the elucidation of the reaction mechanism. We find that a central pore within each monomer traverses the membrane and controls access of cytosolic acetyl-CoA to the active site at its luminal mouth where glucosamine binds. A histidine-aspartic acid catalytic dyad catalyzes the transfer reaction via a ternary complex mechanism. Furthermore, the structures allow the mapping of disease-causing variants and reveal their potential impact on the function, thus creating a framework to guide structure-based drug discovery efforts. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 306.9 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 17.3 KB 17.3 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() | 14.6 KB | Display | ![]() |
Images | ![]() | 96.7 KB | ||
Filedesc metadata | ![]() | 6.1 KB | ||
Others | ![]() ![]() ![]() | 162 MB 301.7 MB 301.7 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8vluMC ![]() 8vkjC ![]() 8vlgC ![]() 8vliC ![]() 8vlvC ![]() 8vlyC M: atomic model generated by this map C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
EMDB pages | ![]() ![]() |
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Map
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Annotation | sharpened map | ||||||||||||||||||||||||||||||||||||
Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 0.813 Å | ||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Additional map: unsharpened map used to build TM1 (residue 191-226)....
File | emd_43344_additional_1.map | ||||||||||||
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Annotation | unsharpened map used to build TM1 (residue 191-226). All other areas are built based on the sharpened map. The entire model is refined against the sharpened map. | ||||||||||||
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Density Histograms |
-Half map: half-map
File | emd_43344_half_map_1.map | ||||||||||||
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Annotation | half-map | ||||||||||||
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Density Histograms |
-Half map: half-map
File | emd_43344_half_map_2.map | ||||||||||||
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Annotation | half-map | ||||||||||||
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Sample components
-Entire : Purified human HGSNAT
Entire | Name: Purified human HGSNAT |
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Components |
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-Supramolecule #1: Purified human HGSNAT
Supramolecule | Name: Purified human HGSNAT / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1 |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 73 KDa |
-Macromolecule #1: Heparan-alpha-glucosaminide N-acetyltransferase
Macromolecule | Name: Heparan-alpha-glucosaminide N-acetyltransferase / type: protein_or_peptide / ID: 1 / Number of copies: 2 / Enantiomer: LEVO / EC number: heparan-alpha-glucosaminide N-acetyltransferase |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 73.365039 KDa |
Recombinant expression | Organism: ![]() |
Sequence | String: MTGARASAAE QRRAGRSGQA RAAERAAGMS GAGRALAALL LAASVLSAAL LAPGGSSGRD AQAAPPRDLD KKRHAELKMD QALLLIHNE LLWTNLTVYW KSECCYHCLF QVLVNVPQSP KAGKPSAAAA SVSTQHGSIL QLNDTLEEKE VCRLEYRFGE F GNYSLLVK ...String: MTGARASAAE QRRAGRSGQA RAAERAAGMS GAGRALAALL LAASVLSAAL LAPGGSSGRD AQAAPPRDLD KKRHAELKMD QALLLIHNE LLWTNLTVYW KSECCYHCLF QVLVNVPQSP KAGKPSAAAA SVSTQHGSIL QLNDTLEEKE VCRLEYRFGE F GNYSLLVK NIHNGVSEIA CDLAVNEDPV DSNLPVSIAF LIGLAVIIVI SFLRLLLSLD DFNNWISKAI SSRETDRLIN SE LGSPSRT DPLDGDVQPA TWRLSALPPR LRSVDTFRGI ALILMVFVNY GGGKYWYFKH ASWNGLTVAD LVFPWFVFIM GSS IFLSMT SILQRGCSKF RLLGKIAWRS FLLICIGIII VNPNYCLGPL SWDKVRIPGV LQRLGVTYFV VAVLELLFAK PVPE HCASE RSCLSLRDIT SSWPQWLLIL VLEGLWLGLT FLLPVPGCPT GYLGPGGIGD FGKYPNCTGG AAGYIDRLLL GDDHL YQHP SSAVLYHTEV AYDPEGILGT INSIVMAFLG VQAGKILLYY KARTKDILIR FTAWCCILGL ISVALTKVSE NEGFIP VNK NLWSLSYVTT LSSFAFFILL VLYPVVDVKG LWTGTPFFYP GMNSILVYVG HEVFENYFPF QWKLKDNQSH KEHLTQN IV ATALWVLIAY ILYRKKIFWK I UniProtKB: Heparan-alpha-glucosaminide N-acetyltransferase |
-Macromolecule #2: 2-acetamido-2-deoxy-beta-D-glucopyranose
Macromolecule | Name: 2-acetamido-2-deoxy-beta-D-glucopyranose / type: ligand / ID: 2 / Number of copies: 7 / Formula: NAG |
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Molecular weight | Theoretical: 221.208 Da |
Chemical component information | ![]() ChemComp-NAG: |
-Macromolecule #3: COENZYME A
Macromolecule | Name: COENZYME A / type: ligand / ID: 3 / Number of copies: 2 / Formula: COA |
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Molecular weight | Theoretical: 767.534 Da |
Chemical component information | ![]() ChemComp-COA: |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Concentration | 3.1 mg/mL |
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Buffer | pH: 7.5 |
Vitrification | Cryogen name: ETHANE |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Average electron dose: 1.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 22.0 µm / Nominal defocus min: 10.0 µm |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |