Annotations: 1EFA

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

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
D [auth B]	d1efab1	All alpha proteins	lambda repressor-like DNA-binding domains	lambda repressor-like DNA-binding domains	GalR/LacI-like bacterial regulator	Lac repressor (LacR), N-terminal domain	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)
D [auth B]	d1efab2	Alpha and beta proteins (a/b)	Periplasmic binding protein-like I	Periplasmic binding protein-like I	L-arabinose binding protein-like	Lac-repressor (lacR) core (C-terminal domain)	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)
C [auth A]	d1efaa1	All alpha proteins	lambda repressor-like DNA-binding domains	lambda repressor-like DNA-binding domains	GalR/LacI-like bacterial regulator	Lac repressor (LacR), N-terminal domain	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)
C [auth A]	d1efaa2	Alpha and beta proteins (a/b)	Periplasmic binding protein-like I	Periplasmic binding protein-like I	L-arabinose binding protein-like	Lac-repressor (lacR) core (C-terminal domain)	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)
E [auth C]	d1efac1	All alpha proteins	lambda repressor-like DNA-binding domains	lambda repressor-like DNA-binding domains	GalR/LacI-like bacterial regulator	Lac repressor (LacR), N-terminal domain	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)
E [auth C]	d1efac2	Alpha and beta proteins (a/b)	Periplasmic binding protein-like I	Periplasmic binding protein-like I	L-arabinose binding protein-like	Lac-repressor (lacR) core (C-terminal domain)	(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)
D [auth B]	SCOP2B Superfamily	Type 1 solute binding protein-like	8037462	3000125	SCOP2B (2022-06-29)
D [auth B]	SCOP2B Superfamily	lambda C1 repressor DNA-binding domain-like	8037209	3000119	SCOP2B (2022-06-29)
C [auth A]	SCOP2 Family	GalR/LacI-like bacterial regulator	8024830	4000900	SCOP2 (2022-06-29)
C [auth A]	SCOP2 Family	Purine repressor, corepressor-binding domain-like	8025083	4007731	SCOP2 (2022-06-29)
C [auth A]	SCOP2 Superfamily	lambda C1 repressor DNA-binding domain-like	8037209	3000119	SCOP2 (2022-06-29)
C [auth A]	SCOP2 Superfamily	Type 1 solute binding protein-like	8037462	3000125	SCOP2 (2022-06-29)
E [auth C]	SCOP2B Superfamily	Type 1 solute binding protein-like	8037462	3000125	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)
D [auth B]	LacI	e1efaB3	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: LacI	ECOD (1.6)
D [auth B]	Peripla_BP_3	e1efaB1	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Periplasmic binding protein-like I	F: Peripla_BP_3	ECOD (1.6)
D [auth B]	Peripla_BP_1_1st_1	e1efaB2	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Periplasmic binding protein-like I	F: Peripla_BP_1_1st_1	ECOD (1.6)
C [auth A]	LacI	e1efaA1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: LacI	ECOD (1.6)
C [auth A]	Peripla_BP_3	e1efaA3	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Periplasmic binding protein-like I	F: Peripla_BP_3	ECOD (1.6)
C [auth A]	Peripla_BP_1_1st_1	e1efaA2	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Periplasmic binding protein-like I	F: Peripla_BP_1_1st_1	ECOD (1.6)
E [auth C]	Peripla_BP_3	e1efaC2	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Periplasmic binding protein-like I	F: Peripla_BP_3	ECOD (1.6)
E [auth C]	Peripla_BP_1_1st_1	e1efaC3	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Periplasmic binding protein-like I	F: Peripla_BP_1_1st_1	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
D [auth B]	1.10.260.40	Mainly Alpha	Orthogonal Bundle	434 Repressor (Amino-terminal Domain)	lambda repressor-like DNA-binding domains	CATH (4.3.0)
D [auth B]	3.40.50.2300	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Response regulator	CATH (4.3.0)
C [auth A]	1.10.260.40	Mainly Alpha	Orthogonal Bundle	434 Repressor (Amino-terminal Domain)	lambda repressor-like DNA-binding domains	CATH (4.3.0)
C [auth A]	3.40.50.2300	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Response regulator	CATH (4.3.0)
E [auth C]	3.40.50.2300	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Response regulator	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
C [auth A], D [auth B], E [auth C]	PF13377	Periplasmic binding protein-like domain (Peripla_BP_3)	Periplasmic binding protein-like domain	This domain is found in a variety of transcriptional regulatory proteins. It is related to bacterial periplasmic binding proteins, although this domain is unlikely to be found in the periplasm. This domain acts as a sensor binding small molecule liga ...	This domain is found in a variety of transcriptional regulatory proteins. It is related to bacterial periplasmic binding proteins, although this domain is unlikely to be found in the periplasm. This domain acts as a sensor binding small molecule ligands that the DNA-binding domain responds to. This domain recognises Sugars, sugar phosphates, sugar acids and purines (Matilla et. al., FEMS Microbiology Reviews, fuab043, 45, 2021, 1. https://doi.org/10.1093/femsre/fuab043).	Domain
C [auth A], D [auth B], E [auth C]	PF00356	Bacterial regulatory proteins, lacI family (LacI)	Bacterial regulatory proteins, lacI family	-	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A [auth D], B [auth E]	DNA (5'-D(GPAPAPTTPGPTPGPAPGPCPGPCPTPCPAPCPAPAPTP*T)-3')	-	-	-
C [auth A], D [auth B], E [auth C]	LAC REPRESSOR	DNA binding sequence-specific DNA binding sequence-specific double-stranded DNA binding transcription cis-regulatory region binding binding double-stranded DNA binding organic cyclic compound binding nucleic acid binding cis-regulatory region sequence-specific DNA binding transcription regulatory region nucleic acid binding transcription regulator activity DNA-binding transcription factor activity identical protein binding protein binding DNA binding sequence-specific DNA binding sequence-specific double-stranded DNA binding transcription cis-regulatory region binding binding double-stranded DNA binding organic cyclic compound binding nucleic acid binding cis-regulatory region sequence-specific DNA binding transcription regulatory region nucleic acid binding transcription regulator activity DNA-binding transcription factor activity identical protein binding protein binding DNA-binding transcription repressor activity	regulation of cellular process negative regulation of biological process RNA metabolic process regulation of primary metabolic process negative regulation of RNA biosynthetic process RNA biosynthetic process nucleobase-containing compound metabolic process DNA-templated transcription nucleic acid biosynthetic process regulation of RNA metabolic process negative regulation of cellular process negative regulation of nucleobase-containing compound metabolic process regulation of nucleobase-containing compound metabolic process regulation of RNA biosynthetic process regulation of cellular process negative regulation of biological process RNA metabolic process regulation of primary metabolic process negative regulation of RNA biosynthetic process RNA biosynthetic process nucleobase-containing compound metabolic process DNA-templated transcription nucleic acid biosynthetic process regulation of RNA metabolic process negative regulation of cellular process negative regulation of nucleobase-containing compound metabolic process regulation of nucleobase-containing compound metabolic process regulation of RNA biosynthetic process negative regulation of macromolecule metabolic process regulation of biosynthetic process negative regulation of DNA-templated transcription regulation of biological process negative regulation of metabolic process biological regulation primary metabolic process regulation of macromolecule metabolic process nucleobase-containing compound biosynthetic process gene expression macromolecule biosynthetic process nucleic acid metabolic process regulation of gene expression biosynthetic process negative regulation of biosynthetic process negative regulation of macromolecule biosynthetic process metabolic process cellular process regulation of macromolecule biosynthetic process macromolecule metabolic process regulation of DNA-templated transcription regulation of metabolic process negative regulation of RNA metabolic process	cellular anatomical structure intracellular anatomical structure cytoplasm cytosol

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
C [auth A], D [auth B], E [auth C]	IPR046335	Transcriptional regulator LacI/GalR-like, sensor domain	Domain
C [auth A], D [auth B], E [auth C]	IPR000843	LacI-type HTH domain	Domain
C [auth A], D [auth B], E [auth C]	IPR028082	Periplasmic binding protein-like I	Homologous Superfamily
C [auth A], D [auth B], E [auth C]	IPR010982	Lambda repressor-like, DNA-binding domain superfamily	Homologous Superfamily

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.