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1n4a

The Ligand Bound Structure of E.coli BtuF, the Periplasmic Binding Protein for Vitamin B12

Method: X-RAY DIFFRACTION Dmax: 75.2 Å Quality: EXCELLENT
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1. Protein Identity and Related Structures Protein Identity & Related Structures

Vitamin B12 transport protein btuF

Escherichia coli

UniProt P37028

State in the Current Structure

Assembly Oligomeric State Construct Mutations and Modifications Ligands, Ions and Associated Components Method and Experimental Conditions Structure Quality
1 Protein monomer Monomer Protein × 1 PDB declaration: monomeric（1） Consistent with protein copy count Chain A； UniProt 23–266 Non-standard monomer：Yes (specific site not provided by mmCIF) CNC CYANOCOBALAMIN × 1 X-RAY DIFFRACTION X-ray crystallization conditions：VAPOR DIFFUSION, HANGING DROP；pH 4.6；294 K；NaCl, ethanol, acetate, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 294K Resolution 2.00 Å R-free 0.261
2 Protein monomer Monomer Protein × 1 PDB declaration: monomeric（1） Consistent with protein copy count Chain B； UniProt 23–266 Non-standard monomer：Yes (specific site not provided by mmCIF) CNC CYANOCOBALAMIN × 1 X-RAY DIFFRACTION X-ray crystallization conditions：VAPOR DIFFUSION, HANGING DROP；pH 4.6；294 K；NaCl, ethanol, acetate, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 294K Resolution 2.00 Å R-free 0.261

Other States of the Same Protein in the Database

Each row is a biological assembly of the same UniProt protein in another PDB entry. The “Difference from current entry” column identifies evidence-level differences; no tag means the currently parsed fields agree.

Other PDB Difference from Current Entry 1N4A Assembly / Oligomeric State Construct Mutations and Modifications Ligands, Ions and Non-polymers Method and Experimental Conditions Structure Quality
1N2Z 2.0 Angstrom structure of BtuF, the vitamin B12 binding protein of E. coli Deposited 2002-10-24 Different construct Different mutation/modification Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain A 22–266（245 aa）
Not recorded CD CADMIUM ION × 13 CL CHLORIDE ION × 4 CNC CYANOCOBALAMIN × 1 PG4 TETRAETHYLENE GLYCOL × 1 X-RAY DIFFRACTION mmCIF provides none of the parsed conditions Resolution 2.00 Å R-free 0.210
1N2Z 2.0 Angstrom structure of BtuF, the vitamin B12 binding protein of E. coli Deposited 2002-10-24 Different construct Different mutation/modification Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 2 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain B 22–266（245 aa）
Not recorded CD CADMIUM ION × 9 CL CHLORIDE ION × 2 CNC CYANOCOBALAMIN × 1 X-RAY DIFFRACTION mmCIF provides none of the parsed conditions Resolution 2.00 Å R-free 0.210
1N2Z 2.0 Angstrom structure of BtuF, the vitamin B12 binding protein of E. coli Deposited 2002-10-24 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 3 Protein homooligomer Homooligomer；Protein × 2 PDB declaration: dimeric
Chain A 22–266（245 aa）
Chain B 22–266（245 aa）
Not recorded CD CADMIUM ION × 22 CL CHLORIDE ION × 6 CNC CYANOCOBALAMIN × 2 PG4 TETRAETHYLENE GLYCOL × 1 X-RAY DIFFRACTION mmCIF provides none of the parsed conditions Resolution 2.00 Å R-free 0.210
1N2Z 2.0 Angstrom structure of BtuF, the vitamin B12 binding protein of E. coli Deposited 2002-10-24 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 4 Protein homooligomer Homooligomer；Protein × 2 PDB declaration: dimeric
Chain A 22–266（245 aa）
Chain B 22–266（245 aa）
Not recorded CD CADMIUM ION × 22 CL CHLORIDE ION × 6 CNC CYANOCOBALAMIN × 2 PG4 TETRAETHYLENE GLYCOL × 1 X-RAY DIFFRACTION mmCIF provides none of the parsed conditions Resolution 2.00 Å R-free 0.210
1N4D The Ligand-Free Structure of E coli BtuF, the Periplasmic Binding Protein for Vitamin B12 Deposited 2002-10-30 Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain A 23–266（244 aa）
Non-standard monomer：Yes (specific site not provided by mmCIF) No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；294 K；acetate, PEG4000, (NH4)OAc, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 294K
Resolution 3.00 Å R-free 0.298
1N4D The Ligand-Free Structure of E coli BtuF, the Periplasmic Binding Protein for Vitamin B12 Deposited 2002-10-30 Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 2 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain B 23–266（244 aa）
Non-standard monomer：Yes (specific site not provided by mmCIF) No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；294 K；acetate, PEG4000, (NH4)OAc, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 294K
Resolution 3.00 Å R-free 0.298
2QI9 ABC-transporter BtuCD in complex with its periplasmic binding protein BtuF Deposited 2007-07-03 Different construct Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric
Chain F 22–266（245 aa）
Non-standard monomer：Yes (specific site not provided by mmCIF) PO4 PHOSPHATE ION × 2 SO4 SULFATE ION × 6 1PE PENTAETHYLENE GLYCOL × 2 PEG DI(HYDROXYETHYL)ETHER × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 8.4；293 K；30-38% (w/v) polyethylene glycol 400, 50mM either of Tris‑HCl pH 8.4 or Glycine-NaOH pH 9.4 and 400mM (NH4)2SO4., VAPOR DIFFUSION, SITTING DROP, temperature 293K
Resolution 2.60 Å R-free 0.280
4DBL Crystal structure of E159Q mutant of BtuCDF Deposited 2012-01-16 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric
Chain E 22–266（245 aa）
Not recorded PO4 PHOSPHATE ION × 2 SO4 SULFATE ION × 6 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 5.4；293 K；0.1M sodium citrate, pH 5.4, 0.3-0.4M ammonium sulphate, 30-35% PEG-400, VAPOR DIFFUSION, SITTING DROP, temperature 293K
Resolution 3.49 Å R-free 0.251
4DBL Crystal structure of E159Q mutant of BtuCDF Deposited 2012-01-16 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 2 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric
Chain J 22–266（245 aa）
Not recorded PO4 PHOSPHATE ION × 2 SO4 SULFATE ION × 6 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 5.4；293 K；0.1M sodium citrate, pH 5.4, 0.3-0.4M ammonium sulphate, 30-35% PEG-400, VAPOR DIFFUSION, SITTING DROP, temperature 293K
Resolution 3.49 Å R-free 0.251
4FI3 Structure of vitamin B12 transporter BtuCD-F in a nucleotide-bound state Deposited 2012-06-07 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric
Chain F 22–266（245 aa） Fragment：UNP residues 22-266
Not recorded ANP PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER × 2 MG MAGNESIUM ION × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 6.8；293 K；20-30% PEG400, 100 mM ADA pH6.8, 100 mM Na/K-citrate, VAPOR DIFFUSION, SITTING DROP, temperature 293K
Resolution 3.47 Å R-free 0.274
5M29 Structure of cobinamide-bound BtuF, the periplasmic vitamin B12 binding protein in E.coli Deposited 2016-10-12 Different construct Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain A 22–266（245 aa）
Non-standard monomer：Yes (specific site not provided by mmCIF) CBY COB(II)INAMIDE × 1 CYN CYANIDE ION × 1 GOL GLYCEROL × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；HEPES sodium pH 7.0 PEG3350 Tryptone
Resolution 1.50 Å R-free 0.213
5M29 Structure of cobinamide-bound BtuF, the periplasmic vitamin B12 binding protein in E.coli Deposited 2016-10-12 Different construct Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 2 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain B 22–266（245 aa）
Non-standard monomer：Yes (specific site not provided by mmCIF) CBY COB(II)INAMIDE × 1 CYN CYANIDE ION × 2 GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；HEPES sodium pH 7.0 PEG3350 Tryptone
Resolution 1.50 Å R-free 0.213
5M2Q Structure of cobinamide-bound BtuF mutant W66F, the periplasmic vitamin B12 binding protein in E.coli Deposited 2016-10-13 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Insufficient information Monomer；Protein × 1 PDB declaration: monomeric
Chain A 22–266（245 aa）
Mutation：W66F CBY COB(II)INAMIDE × 1 CYN CYANIDE ION × 1 GOL GLYCEROL × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG3350 HEPES pH 7 Tryptone
Resolution 1.70 Å R-free 0.249
5M2Q Structure of cobinamide-bound BtuF mutant W66F, the periplasmic vitamin B12 binding protein in E.coli Deposited 2016-10-13 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 2 Insufficient information Monomer；Protein × 1 PDB declaration: monomeric
Chain B 22–266（245 aa）
Mutation：W66F CBY COB(II)INAMIDE × 1 CYN CYANIDE ION × 1 GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG3350 HEPES pH 7 Tryptone
Resolution 1.70 Å R-free 0.249
5M34 Structure of cobinamide-bound BtuF mutant W66Y, the periplasmic vitamin B12 binding protein in E.coli Deposited 2016-10-14 Different construct Different mutation/modification Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain A 22–266（245 aa）
Not recorded CBY COB(II)INAMIDE × 1 CYN CYANIDE ION × 1 GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG3350 HEPES pH 7 Tryptone
Resolution 1.60 Å R-free 0.233
5M34 Structure of cobinamide-bound BtuF mutant W66Y, the periplasmic vitamin B12 binding protein in E.coli Deposited 2016-10-14 Different construct Different mutation/modification Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 2 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain B 22–266（245 aa）
Not recorded CBY COB(II)INAMIDE × 1 CYN CYANIDE ION × 2 GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG3350 HEPES pH 7 Tryptone
Resolution 1.60 Å R-free 0.233
5M3B Structure of cobinamide-bound BtuF mutant W66L, the periplasmic vitamin B12 binding protein in E.coli Deposited 2016-10-14 Different construct Different mutation/modification Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain A 22–266（245 aa）
Not recorded CYN CYANIDE ION × 2 CBY COB(II)INAMIDE × 1 GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG3350 HEPES pH 7 Tryptone
Resolution 1.50 Å R-free 0.229
5M3B Structure of cobinamide-bound BtuF mutant W66L, the periplasmic vitamin B12 binding protein in E.coli Deposited 2016-10-14 Different construct Different mutation/modification Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 2 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric
Chain B 22–266（245 aa）
Not recorded CYN CYANIDE ION × 1 CBY COB(II)INAMIDE × 1 GOL GLYCEROL × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG3350 HEPES pH 7 Tryptone
Resolution 1.50 Å R-free 0.229
5OVW Nanobody-bound BtuF, the vitamin B12 binding protein in Escherichia coli Deposited 2017-08-30 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 1 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric
Chain A 22–266（245 aa）
Not recorded GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG4000, Tris-HCl, Magnesium chloride
Resolution 2.65 Å R-free 0.259
5OVW Nanobody-bound BtuF, the vitamin B12 binding protein in Escherichia coli Deposited 2017-08-30 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 2 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric
Chain B 22–266（245 aa）
Not recorded GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG4000, Tris-HCl, Magnesium chloride
Resolution 2.65 Å R-free 0.259
5OVW Nanobody-bound BtuF, the vitamin B12 binding protein in Escherichia coli Deposited 2017-08-30 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 3 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric
Chain C 22–266（245 aa）
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG4000, Tris-HCl, Magnesium chloride
Resolution 2.65 Å R-free 0.259
5OVW Nanobody-bound BtuF, the vitamin B12 binding protein in Escherichia coli Deposited 2017-08-30 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 4 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric
Chain D 22–266（245 aa）
Not recorded GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG4000, Tris-HCl, Magnesium chloride
Resolution 2.65 Å R-free 0.259
5OVW Nanobody-bound BtuF, the vitamin B12 binding protein in Escherichia coli Deposited 2017-08-30 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 5 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric
Chain E 22–266（245 aa）
Not recorded GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG4000, Tris-HCl, Magnesium chloride
Resolution 2.65 Å R-free 0.259
5OVW Nanobody-bound BtuF, the vitamin B12 binding protein in Escherichia coli Deposited 2017-08-30 Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics Assembly 6 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric
Chain F 22–266（245 aa）
Not recorded GOL GLYCEROL × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；293.15 K；PEG4000, Tris-HCl, Magnesium chloride
Resolution 2.65 Å R-free 0.259

10 other PDB entries and 24 assemblies. Open the comparison page and filter oligomeric states

View Construct and Data Evidence
UniProt name BTUF_ECOLI
Isoform —
PDB entities 1
Chains and sequence ranges Author chain A； PDBConstruct 1–244； UniProt 23–266 Author chain B； PDBConstruct 1–244； UniProt 23–266

The page prioritizes protein identity, the current assembly, associated components, oligomeric state and cross-PDB links. Chain mapping and sequence ranges are retained as data evidence. Internal IDs, import timestamps and assembly operation expressions are maintenance fields and are not shown here.

SAXS scattering curve SAXS Profile

SAXS profile for 1n4a

P(r) Distance Distribution P(r) Distribution

P(r) distribution for 1n4a
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2. Structure Basics 2. Structure Basics

Entry ID entry_id1n4a
Deposition date deposition_date2002-10-30
Structure title titleThe Ligand Bound Structure of E.coli BtuF, the Periplasmic Binding Protein for Vitamin B12
Keywords keywords;ABC transporter, periplasmic binding protein, Vitamin B12, transmembrane transport, Structural Genomics, PSI, Protein Structure Initiative, Northeast Structural Genomics Consortium, NESG, TRANSPORT PROTEIN ;; TRANSPORT PROTEIN
Experimental Method methodX-RAY DIFFRACTION
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3. SAXS Parameters (CRYSOL theoretical calculation) 3. SAXS Parameters (CRYSOL)

Radius of gyration Rg (Guinier) rg_guinier24.30 Å
Radius of gyration Rg (electron density) rg_electron23.41 Å
Forward intensity I(0) i051611300.00
Molecular weight molecular_weight56776.0 kDa
Excluded volume excluded_volume71457 ų
Envelope volume envelope_volume83901 ų
Hydration-shell volume shell_volume29311 ų
Envelope diameter envelope_diameter76.8 Å
Shell Rg shell_rg31.07 Å
Envelope Rg envelope_rg23.49 Å
Shape Rg shape_rg23.41 Å
Total Rg total_rg24.26 Å
Total atoms total_atoms3990
Residues n_residues484
Spherical-harmonic order n_harmonics20
q range q_range— – 0.5000 Å−1
Data points n_points101
Shell type shell_typedirectional
Solvent electron density solvent_density0.3340 e/ų
Shell contrast contrast_shell0.0300 e/ų
CRYSOL version crysol_version4.1.3
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4. P(r) Distance Distribution (GNOM inversion) 4. P(r) Analysis (GNOM)

Maximum dimension Dmax dmax75.2 Å
Rg (real space) rg_real24.16 Å
Rg uncertainty (real space) rg_real_error0.41 Å
I(0) (real space) i0_real5.1610e+07
I(0) uncertainty (real space) i0_real_error6.6180e+05
Rg (reciprocal space) rg_reciprocal24.19 Å
I(0) (reciprocal space) i0_reciprocal51610000.0000
Solution quality estimate total_estimate0.9055
Solution quality rating solution_quality EXCELLENT a EXCELLENT solution
P(r) peaks n_peaks2
Primary peak position r_peak_primary29.9 Å
Skewness Skewness skewness0.180
Kurtosis Kurtosis kurtosis-0.488
Angular range angular_range— – 0.3250 Å−1
Current regularization parameter α current_alpha0.0000
Highest regularization parameter α highest_alpha16830000.0000
Real-space data points n_real_points64
GNOM version gnom_version4.1.3
Quality Criteria quality_criteria AN1: 0.000; Oscil: 0.929; Stabil: 1.000; Sysdev: 1.000; Positv: 1.000; Valcen: 0.997; Smooth: 0.983
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5. Crystallography and Experiment 5. Crystallography & Experiment

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6. Entities and Polymers Entities & Polymers (3)

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7. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

Domain ID domain_idd1n4aa_
Class classc — Alpha and beta proteins (a/b)
Fold Fold foldc.92 — Chelatase-like
Superfamily Superfamily superfamilyc.92.2 — 'Helical backbone' metal receptor
Family Family familyc.92.2.2 — TroA-like
Domain ID domain_idd1n4ab_
Class classc — Alpha and beta proteins (a/b)
Fold Fold foldc.92 — Chelatase-like
Superfamily Superfamily superfamilyc.92.2 — 'Helical backbone' metal receptor
Family Family familyc.92.2.2 — TroA-like

CATH v4.4 (4 domains)

Domain ID domain_id1n4aA01
Class class3 — Alpha Beta
Architecture architecture40 — 3-Layer(aba) Sandwich
Topology topology50 — Rossmann fold
Homologous superfamily homologous superfamily1980 — Nitrogenase molybdenum iron protein domain
Domain ID domain_id1n4aA02
Class class3 — Alpha Beta
Architecture architecture40 — 3-Layer(aba) Sandwich
Topology topology50 — Rossmann fold
Homologous superfamily homologous superfamily1980 — Nitrogenase molybdenum iron protein domain
Domain ID domain_id1n4aB01
Class class3 — Alpha Beta
Architecture architecture40 — 3-Layer(aba) Sandwich
Topology topology50 — Rossmann fold
Homologous superfamily homologous superfamily1980 — Nitrogenase molybdenum iron protein domain
Domain ID domain_id1n4aB02
Class class3 — Alpha Beta
Architecture architecture40 — 3-Layer(aba) Sandwich
Topology topology50 — Rossmann fold
Homologous superfamily homologous superfamily1980 — Nitrogenase molybdenum iron protein domain
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8. Citations (1)

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9. Files and Curves (10)