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- PDB-7wlg: Cryo-EM structure of GH31 alpha-1,3-glucosidase from Lactococcus ... -
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Open data
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Basic information
Entry | Database: PDB / ID: 7wlg | |||||||||
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Title | Cryo-EM structure of GH31 alpha-1,3-glucosidase from Lactococcus lactis subsp. cremoris | |||||||||
![]() | Alpha-xylosidase | |||||||||
![]() | HYDROLASE / nigerose / glucose / glycoside hydrolase / GH31 / carbohydrate / TIM-barrel / hexamer | |||||||||
Function / homology | ![]() Hydrolases; Glycosylases; Glycosidases, i.e. enzymes that hydrolyse O- and S-glycosyl compounds / hydrolase activity, hydrolyzing O-glycosyl compounds / carbohydrate metabolic process Similarity search - Function | |||||||||
Biological species | ![]() | |||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.73 Å | |||||||||
![]() | Ikegaya, M. / Moriya, T. / Adachi, N. / Kawasaki, M. / Park, E.Y. / Miyazaki, T. | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural basis of the strict specificity of a bacterial GH31 α-1,3-glucosidase for nigerooligosaccharides. Authors: Marina Ikegaya / Toshio Moriya / Naruhiko Adachi / Masato Kawasaki / Enoch Y Park / Takatsugu Miyazaki / ![]() Abstract: Carbohydrate-active enzymes are involved in the degradation, biosynthesis, and modification of carbohydrates and vary with the diversity of carbohydrates. The glycoside hydrolase (GH) family 31 is ...Carbohydrate-active enzymes are involved in the degradation, biosynthesis, and modification of carbohydrates and vary with the diversity of carbohydrates. The glycoside hydrolase (GH) family 31 is one of the most diverse families of carbohydrate-active enzymes, containing various enzymes that act on α-glycosides. However, the function of some GH31 groups remains unknown, as their enzymatic activity is difficult to estimate due to the low amino acid sequence similarity between characterized and uncharacterized members. Here, we performed a phylogenetic analysis and discovered a protein cluster (GH31_u1) sharing low sequence similarity with the reported GH31 enzymes. Within this cluster, we showed that a GH31_u1 protein from Lactococcus lactis (LlGH31_u1) and its fungal homolog demonstrated hydrolytic activities against nigerose [α-D-Glcp-(1→3)-D-Glc]. The k/K values of LlGH31_u1 against kojibiose and maltose were 13% and 2.1% of that against nigerose, indicating that LlGH31_u1 has a higher specificity to the α-1,3 linkage of nigerose than other characterized GH31 enzymes, including eukaryotic enzymes. Furthermore, the three-dimensional structures of LlGH31_u1 determined using X-ray crystallography and cryogenic electron microscopy revealed that LlGH31_u1 forms a hexamer and has a C-terminal domain comprising four α-helices, suggesting that it contributes to hexamerization. Finally, crystal structures in complex with nigerooligosaccharides and kojibiose along with mutational analysis revealed the active site residues involved in substrate recognition in this enzyme. This study reports the first structure of a bacterial GH31 α-1,3-glucosidase and provides new insight into the substrate specificity of GH31 enzymes and the physiological functions of bacterial and fungal GH31_u1 members. | |||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 758.8 KB | Display | ![]() |
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PDB format | ![]() | 638.8 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.3 MB | Display | ![]() |
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Full document | ![]() | 1.3 MB | Display | |
Data in XML | ![]() | 126.7 KB | Display | |
Data in CIF | ![]() | 189.8 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 32571MC ![]() 7wj9C ![]() 7wjaC ![]() 7wjbC ![]() 7wjcC ![]() 7wjdC ![]() 7wjeC ![]() 7wjfC C: citing same article ( M: map data used to model this data |
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Similar structure data | Similarity search - Function & homology ![]() |
EM raw data | ![]() Data size: 911.2 Data #1: Cryo-EM structure of GH31 alpha-1,3-glucosidase from Lactococcus lactis subsp. cremoris [micrographs - multiframe]) |
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Links
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Assembly
Deposited unit | ![]()
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Components
#1: Protein | Mass: 88028.484 Da / Num. of mol.: 6 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() Strain: MG1363 / Gene: llmg_1836 / Plasmid: pET28a / Production host: ![]() ![]() References: UniProt: A2RM80, Hydrolases; Glycosylases; Glycosidases, i.e. enzymes that hydrolyse O- and S-glycosyl compounds |
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-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
Component | Name: LlGH31_u1 / Type: COMPLEX / Entity ID: all / Source: RECOMBINANT | |||||||||||||||
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Molecular weight | Value: 0.516 MDa / Experimental value: NO | |||||||||||||||
Source (natural) | Organism: ![]() | |||||||||||||||
Source (recombinant) | Organism: ![]() ![]() | |||||||||||||||
Buffer solution | pH: 7 | |||||||||||||||
Buffer component |
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Specimen | Conc.: 0.58 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES / Details: This sample was mono-disperse | |||||||||||||||
Specimen support | Details: The grid was washed by acetone prior to use. / Grid material: COPPER / Grid mesh size: 300 divisions/in. / Grid type: Quantifoil R1.2/1.3 | |||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 291 K / Details: Blotting time was 5 seconds (blot force 15) |
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Electron microscopy imaging
Microscopy | Model: TFS TALOS |
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Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal magnification: 120000 X / Nominal defocus max: 2000 nm / Nominal defocus min: 800 nm / Cs: 2.7 mm / C2 aperture diameter: 50 µm |
Specimen holder | Cryogen: NITROGEN |
Image recording | Average exposure time: 65.95 sec. / Electron dose: 50 e/Å2 / Detector mode: COUNTING / Film or detector model: FEI FALCON III (4k x 4k) / Num. of grids imaged: 1 / Num. of real images: 995 |
Image scans | Width: 4096 / Height: 4096 |
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Processing
Software | Name: PHENIX / Version: 1.19.2_4158: / Classification: refinement | ||||||||||||||||||||||||||||||||||||||||
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EM software |
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CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 267294 | ||||||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: D3 (2x3 fold dihedral) | ||||||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 2.73 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 44606 / Algorithm: FOURIER SPACE / Num. of class averages: 1 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||
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