[English] 日本語
Yorodumi- PDB-8q4y: Beta-galactosidase from Bacillus circulans conformational state 1 -
+
Open data
-
Basic information
| Entry | Database: PDB / ID: 8q4y | ||||||
|---|---|---|---|---|---|---|---|
| Title | Beta-galactosidase from Bacillus circulans conformational state 1 | ||||||
Components | beta-galactosidase | ||||||
Keywords | HYDROLASE / Galactosidase / Transgalactosylation / Izoform A / Enzyme | ||||||
| Function / homology | Function and homology information | ||||||
| Biological species | Niallia circulans (bacteria) | ||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 4 Å | ||||||
Authors | Kascakova, B. / Hovorkova, M. / Petraskova, L. / Novacek, J. / Pinkas, D. / Gardian, Z. / Kren, V. / Bojarova, P. / Kuta Smatanova, I. | ||||||
| Funding support | Czech Republic, 1items
| ||||||
Citation | Journal: Structure / Year: 2024Title: The variable structural flexibility of the Bacillus circulans β-galactosidase isoforms determines their unique functionalities. Authors: Michaela Hovorková / Barbora Kaščáková / Lucie Petrásková / Petra Havlíčková / Jiří Nováček / Daniel Pinkas / Zdenko Gardian / Vladimír Křen / Pavla Bojarová / Ivana Kutá Smatanová / ![]() Abstract: β-Galactosidase from Bacillus circulans ATCC 31382 (BgaD) is a biotechnologically important enzyme for the synthesis of β-galactooligosaccharides (GOS). Among its four isoforms, isoform A (BgaD-A) ...β-Galactosidase from Bacillus circulans ATCC 31382 (BgaD) is a biotechnologically important enzyme for the synthesis of β-galactooligosaccharides (GOS). Among its four isoforms, isoform A (BgaD-A) has distinct synthetic properties. Here, we present cryoelectron microscopy (cryo-EM) structures of BgaD-A and compare them with the known X-ray crystal structure of isoform D (BgaD-D), revealing substantial structural divergences between the two isoforms. In contrast to BgaD-D, BgaD-A features a flexible Big-4 domain and another enigmatic domain. The newly identified flexible region in BgaD-A is termed as "barrier domain 8," and serves as a barricade, obstructing the access of longer oligosaccharide substrates into the active site of BgaD-A. The transgalactosylation reactions catalyzed by both isoforms revealed that BgaD-A has a higher selectivity than BgaD-D in the earlier stages of the reaction and is prevailingly directed to shorter galactooligosaccharides. This study improves our understanding of the structural determinants governing β-galactosidase catalysis, with implications for tailored GOS production. | ||||||
| History |
|
-
Structure visualization
| Structure viewer | Molecule: Molmil Jmol/JSmol |
|---|
-
Downloads & links
-
Download
| PDBx/mmCIF format | 8q4y.cif.gz | 482.4 KB | Display | PDBx/mmCIF format |
|---|---|---|---|---|
| PDB format | pdb8q4y.ent.gz | 325.6 KB | Display | PDB format |
| PDBx/mmJSON format | 8q4y.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Summary document | 8q4y_validation.pdf.gz | 1.4 MB | Display | wwPDB validaton report |
|---|---|---|---|---|
| Full document | 8q4y_full_validation.pdf.gz | 1.4 MB | Display | |
| Data in XML | 8q4y_validation.xml.gz | 42.5 KB | Display | |
| Data in CIF | 8q4y_validation.cif.gz | 62.4 KB | Display | |
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/q4/8q4y ftp://data.pdbj.org/pub/pdb/validation_reports/q4/8q4y | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 18153MC ![]() 8q2hC ![]() 8q51C ![]() 18152 ![]() 18154 M: map data used to model this data C: citing same article ( |
|---|---|
| Similar structure data | Similarity search - Function & homology F&H Search |
-
Links
-
Assembly
| Deposited unit | ![]()
|
|---|---|
| 1 |
|
-
Components
| #1: Protein | Mass: 192584.391 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Niallia circulans (bacteria) / Gene: bga / Variant: ATCC 31382 / Production host: ![]() |
|---|---|
| Has protein modification | N |
-Experimental details
-Experiment
| Experiment | Method: ELECTRON MICROSCOPY |
|---|---|
| EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
-
Sample preparation
| Component | Name: Terciary complex of beta-galactosidase isoform A / Type: COMPLEX / Entity ID: all / Source: RECOMBINANT |
|---|---|
| Molecular weight | Experimental value: NO |
| Source (natural) | Organism: Niallia circulans subsp. circulans (bacteria) |
| Source (recombinant) | Organism: ![]() |
| Buffer solution | pH: 6 / Details: 50 mM sodium phosphate buffer pH 6 |
| Buffer component | Conc.: 2.0 mg/ml / Name: sodium phosphate |
| Specimen | Conc.: 0.18 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
| Vitrification | Cryogen name: ETHANE |
-
Electron microscopy imaging
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
|---|---|
| Microscopy | Model: FEI TITAN KRIOS |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 2400 nm / Nominal defocus min: 1200 nm / Cs: 2.7 mm / C2 aperture diameter: 30 µm |
| Image recording | Average exposure time: 5 sec. / Electron dose: 60 e/Å2 / Detector mode: COUNTING / Film or detector model: GATAN K2 QUANTUM (4k x 4k) |
-
Processing
| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3D reconstruction | Resolution: 4 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 265100 / Symmetry type: POINT | ||||||||||||||||||||||||
| Refinement | Cross valid method: NONE Stereochemistry target values: GeoStd + Monomer Library + CDL v1.2 | ||||||||||||||||||||||||
| Displacement parameters | Biso mean: 134.21 Å2 | ||||||||||||||||||||||||
| Refine LS restraints |
|
Movie
Controller
About Yorodumi



Niallia circulans (bacteria)
Czech Republic, 1items
Citation





PDBj



FIELD EMISSION GUN