Annotations: 1QXX

Domain Annotation: SCOP/SCOPe Classification SCOP Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d1qxxa_	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	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_C	e1qxxA1	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	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	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	TonB protein	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 organic substance 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	IPR006260	TonB/TolA, C-terminal	Domain
A	IPR003538	Gram-negative bacterial TonB protein	Family
A	IPR037682	TonB, C-terminal	Domain

RCSB PDB Core Operations are funded by the National Science Foundation (DBI-1832184), 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 R01GM133198.