2GSK

Structure of the BtuB:TonB Complex

External Resource: Annotation

Domain Annotation: SCOP/SCOPe Classification
Domain Annotation: SCOP2 Classification
Domain Annotation: ECOD Classification
Domain Annotation: CATH
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Membrane Protein Annotation: OPM
Membrane Protein Annotation: PDBTM
Membrane Protein Annotation: MemProtMD
Membrane Protein Annotation: mpstruc

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d2gska_	Membrane and cell surface proteins and peptides	Transmembrane beta-barrels	Porins	Ligand-gated protein channel	Outer membrane cobalamin transporter BtuB	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)
B	d2gskb_	Alpha and beta proteins (a+b)	TolA/TonB C-terminal domain	TolA/TonB C-terminal domain	TonB	TonB	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2 Family	Ligand-gated protein channel	8029650	4003084	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Porins	8042029	3000224	SCOP2 (2022-06-29)
B	SCOP2B Superfamily	TolA/TonB C-terminal domain-like	8042743	3000464	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	TonB_dep_Rec	e2gskA1	A: beta barrels	X: Outer membrane meander beta-barrels	H: Porins	T: Ligand-gated protein channel	F: TonB_dep_Rec	ECOD (1.6)
A	Plug	e2gskA2	A: a+b complex topology	X: N0 domain in phage tail proteins and secretins-like	H: TonB-dependent receptor plug domain (From Topology)	T: TonB-dependent receptor plug domain	F: Plug	ECOD (1.6)
B	TonB_C	e2gskB1	A: a+b two layers	X: TolA/TonB C-terminal domain	H: TolA/TonB C-terminal domain (From Topology)	T: TolA/TonB C-terminal domain	F: TonB_C	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	2.170.130.10	Mainly Beta	Beta Complex	Ferric Hydroxamate Uptake Protein	Chain A, domain 1	CATH (4.3.0)
A	2.40.170.20	Mainly Beta	Beta Barrel	Maltoporin	Chain A	CATH (4.3.0)
B	3.30.2420.10	Alpha Beta	2-Layer Sandwich	TolA/TonB C-terminal domain	TonB	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A	PF00593	TonB dependent receptor-like, beta-barrel (TonB_dep_Rec_b-barrel)	TonB dependent receptor-like, beta-barrel	This entry represents the beta-barrel domain of TonB-dependent receptors, such as BtuB, CirA, FatA, FcuT, FecA, FepA, among others [1].	Domain
A	PF07715	TonB-dependent Receptor Plug Domain (Plug)	TonB-dependent Receptor Plug Domain	The Plug domain has been shown to be an independently folding subunit of the TonB-dependent receptors ([1]). It acts as the channel gate, blocking the pore until the channel is bound by ligand. At this point it under goes conformational changes opens ...	The Plug domain has been shown to be an independently folding subunit of the TonB-dependent receptors ([1]). It acts as the channel gate, blocking the pore until the channel is bound by ligand. At this point it under goes conformational changes opens the channel.	Domain
B	PF03544	Gram-negative bacterial TonB protein C-terminal (TonB_C)	Gram-negative bacterial TonB protein C-terminal	The TonB_C domain is the well-characterised C-terminal region of the TonB receptor molecule. This protein is bound to an inner membrane-bound protein ExbB via a globular domain and has a flexible middle region that is likely to help in positioning th ...	The TonB_C domain is the well-characterised C-terminal region of the TonB receptor molecule. This protein is bound to an inner membrane-bound protein ExbB via a globular domain and has a flexible middle region that is likely to help in positioning the C-terminal domain into the iron-transporter barrel in the outer membrane [1]. TonB_C interacts with the N-terminal TonB box of the outer membrane transporter that binds the Fe3+-siderophore complex. The barrel of the transporter, consisting of 22 beta-sheets and an inside plug, binds the iron complex in the barrel entrance [2].	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A	Vitamin B12 transporter btuB	cation binding ion binding binding calcium ion binding metal ion binding small molecule binding wide pore channel activity passive transmembrane transporter activity channel activity porin activity transporter activity transmembrane transporter activity protein binding protein domain specific binding cation binding ion binding binding calcium ion binding metal ion binding small molecule binding wide pore channel activity passive transmembrane transporter activity channel activity porin activity transporter activity transmembrane transporter activity protein binding protein domain specific binding ABC-type vitamin B12 transporter activity ABC-type transporter activity active transmembrane transporter activity vitamin transmembrane transporter activity primary active transmembrane transporter activity ATPase-coupled transmembrane transporter activity ATP-dependent activity	localization nitrogen compound transport transport vitamin transport cobalamin transport establishment of localization transmembrane transport monoatomic ion transmembrane transport monoatomic ion transport cellular process	membrane cellular anatomical entity protein-containing complex transmembrane transporter complex membrane protein complex transporter complex pore complex cell periphery cell outer membrane external encapsulating structure cell envelope outer membrane
B	protein TONB	molecular transducer activity energy transducer activity protein binding binding protein domain specific binding	intracellular iron ion homeostasis inorganic ion homeostasis cellular homeostasis chemical homeostasis homeostatic process intracellular monoatomic cation homeostasis monoatomic ion homeostasis intracellular chemical homeostasis monoatomic cation homeostasis intracellular monoatomic ion homeostasis localization nitrogen compound transport transport vitamin transport intracellular iron ion homeostasis inorganic ion homeostasis cellular homeostasis chemical homeostasis homeostatic process intracellular monoatomic cation homeostasis monoatomic ion homeostasis intracellular chemical homeostasis monoatomic cation homeostasis intracellular monoatomic ion homeostasis localization nitrogen compound transport transport vitamin transport cobalamin transport establishment of localization protein localization establishment of protein localization cellular localization protein transport cellular macromolecule localization macromolecule localization cellular process virion attachment to host cell biological process involved in interspecies interaction between organisms adhesion of symbiont to host cell viral life cycle adhesion of symbiont to host receptor-mediated bacteriophage irreversible attachment to host cell biological process involved in interaction with host biological process involved in symbiotic interaction receptor-mediated virion attachment to host cell entry receptor-mediated virion attachment to host cell viral process siderophore transport iron ion transport transition metal ion transport monoatomic ion transport monoatomic cation transport metal ion transport iron coordination entity transport transmembrane transport colicin transport amide transport bacteriocin transport	membrane cellular anatomical entity cell periphery protein-containing complex plasma membrane protein complex plasma membrane membrane protein complex transmembrane transporter complex transporter complex outer membrane-bounded periplasmic space cell envelope periplasmic space cell outer membrane external encapsulating structure membrane cellular anatomical entity cell periphery protein-containing complex plasma membrane protein complex plasma membrane membrane protein complex transmembrane transporter complex transporter complex outer membrane-bounded periplasmic space cell envelope periplasmic space cell outer membrane external encapsulating structure outer membrane

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A	IPR039426	TonB-dependent receptor-like	Family
A	IPR037066	TonB-dependent receptor, plug domain superfamily	Homologous Superfamily
A	IPR010917	TonB-dependent receptor, conserved site	Conserved Site
A	IPR036942	TonB-dependent receptor-like, beta-barrel domain superfamily	Homologous Superfamily
A	IPR012910	TonB-dependent receptor, plug domain	Domain
A	IPR010916	TonB box, conserved site	Conserved Site
A	IPR010101	TonB-dependent vitamin B12 transporter BtuB	Family
A	IPR000531	TonB-dependent receptor-like, beta-barrel	Domain
B	IPR051045	TonB-dependent transporter energy transducer	Family
B	IPR006260	TonB/TolA, C-terminal	Domain
B	IPR003538	Gram-negative bacterial TonB protein	Family
B	IPR049924	TonB, proline-rich region	Domain
B	IPR037682	TonB, C-terminal	Domain

Membrane Protein Annotation: OPM OPM Database Homepage

Chains	External Link	Type	Class	Superfamily	Family
A, B	OPM	Transmembrane	Beta-barrel transmembrane	Ligand-gated protein channels (n=22,S=24)	Outer Membrane Receptor (OMR)

Membrane Protein Annotation: PDBTM PDBTM Database Homepage

Chains	External Link	Comment
A, B	PDBTM	Annotated as membrane protein by PDBTM

Membrane Protein Annotation: MemProtMD MemProtMD Database Homepage

Chains	External Link	Comment
A, B	MemProtMD	Annotated as membrane protein by MemProtMD

Membrane Protein Annotation: mpstruc mpstruc Database Homepage

Chains	Resource Link	Group	Subgroup	Protein
A, B	mpstruc	TRANSMEMBRANE PROTEINS: BETA-BARREL	Beta-Barrel Membrane Proteins: Monomeric/Dimeric	BtuB in complex with TonB

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729.