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1nqg

OUTER MEMBRANE COBALAMIN TRANSPORTER (BTUB) FROM E. COLI, WITH BOUND CALCIUM

Method: X-RAY DIFFRACTION
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1. Protein Identity and Related Structures Protein Identity & Related Structures

vitamin b12 receptor

Escherichia coli

UniProt P06129

State in the Current Structure

Assembly Physical composition Protein state Molecular copy count Associated components Data consistency
1 Protein monomer Monomer Protein 1 CALCIUM ION × 4 (HYDROXYETHYLOXY)TRI(ETHYLOXY)OCTANE × 6 Consistent with protein count

Other States of the Same Protein in the Database

Monomer
1nqe 1nqf 1nqg 1nqh 2guf 3m8b 3m8d 3rgm 3rgn

9 assemblies

Homodimer

None

Homotetramer

None

Other homooligomers

None

Heteromeric or nucleic-acid complex
1ujw 2gsk 2ysu 7nsu

4 assemblies

View Construct and Data Evidence
UniProt name BTUB_ECOLI
Isoform —
PDB entities 1
Chains and sequence ranges Author chain A； PDBConstruct 1–594； UniProt 21–614

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.

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2. Structure Basics 2. Structure Basics

Entry ID entry_id1nqg
Deposition date deposition_date2003-01-21
Structure title titleOUTER MEMBRANE COBALAMIN TRANSPORTER (BTUB) FROM E. COLI, WITH BOUND CALCIUM
Keywords keywordsBeta barrel, cobalamin, VITAMIN B12, membrane transport, calcium binding, TRANSPORT PROTEIN; TRANSPORT PROTEIN
Experimental Method methodX-RAY DIFFRACTION
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3. Official assembly/model SAXS Official SAXS Profiles

This page reads only the latest assembly calculations. Every curve maps to an explicit PDB entry, official biological assembly and coordinate model.

1nqg__assembly_1__model_1

Assembly 1 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

1nqg__assembly_1__model_1 | I(q)

10-2 10-1 106 107 q (1/Angstrom) I(q)
100 plotted points; both axes use logarithmic scales.

1nqg__assembly_1__model_1 | P(r) · Pending

The new assembly/model P(r) has not been calculated yet This placeholder does not display legacy data r (Angstrom) P(r)
P(r) will be calculated and displayed separately for the same assembly/model.
Rg（Guinier）24.52 Å
Rg (electron density)23.76 Å
Total Rg24.65 Å
Atom count4685
Residues576
Excluded volume82552 ų
Maximum q0.500 Å⁻¹
Assembly Model Structure unit Oligomeric description Status CRYSOL Actions
1 1 1nqg__assembly_1__model_1 monomeric （1） Success 4.1.3-1-20251215 (887e7ef) View Download
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4. Crystallography and Experiment 4. Crystallography & Experiment

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5. Entities and Polymers Entities & Polymers (3)

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6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (1 domains)

Domain ID domain_idd1nqga_
Class classf — Membrane and cell surface proteins and peptides
Fold Fold foldf.4 — Transmembrane beta-barrels
Superfamily Superfamily superfamilyf.4.3 — Porins
Family Family familyf.4.3.3 — Ligand-gated protein channel

CATH v4.4 (2 domains)

Domain ID domain_id1nqgA01
Class class2 — Mainly Beta
Architecture architecture170 — Beta Complex
Topology topology130 — Ferric Hydroxamate Uptake Protein; Chain A, domain 1
Homologous superfamily homologous superfamily10 — TonB-dependent receptor, plug domain
Domain ID domain_id1nqgA02
Class class2 — Mainly Beta
Architecture architecture40 — Beta Barrel
Topology topology170 — Maltoporin; Chain A
Homologous superfamily homologous superfamily20 — TonB-dependent receptor, beta-barrel domain
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7. Citations (2)