Annotations: 1FCB

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

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d1fcba1	Alpha and beta proteins (a/b)	TIM beta/alpha-barrel	FMN-linked oxidoreductases	FMN-linked oxidoreductases	Flavocytochrome b2, C-terminal domain	baker's yeast (Saccharomyces cerevisiae ) [TaxId: 4932 ],	SCOPe (2.08)
A	d1fcba2	Alpha and beta proteins (a+b)	Cytochrome b5-like heme/steroid binding domain	Cytochrome b5-like heme/steroid binding domain	Cytochrome b5	Flavocytochrome b2, N-terminal domain	baker's yeast (Saccharomyces cerevisiae ) [TaxId: 4932 ],	SCOPe (2.08)
B	d1fcbb_	Alpha and beta proteins (a/b)	TIM beta/alpha-barrel	FMN-linked oxidoreductases	FMN-linked oxidoreductases	Flavocytochrome b2, C-terminal domain	baker's yeast (Saccharomyces cerevisiae ) [TaxId: 4932 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2B Superfamily	Cytochrome b5-like heme/steroid binding domain	8003822	3000073	SCOP2B (2022-06-29)
A	SCOP2B Superfamily	FMN-linked oxidoreductases	8017532	3000014	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	FMN-linked oxidoreductases	8017532	3000014	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	Cyt-b5	e1fcbA1	A: a+b two layers	X: Cystatin-like	H: Cytochrome b5-like heme/steroid binding domain (From Topology)	T: Cytochrome b5-like heme/steroid binding domain	F: Cyt-b5	ECOD (1.6)
A	Glu_synthase	e1fcbA2	A: a/b barrels	X: TIM beta/alpha-barrel	H: TIM barrels (From Topology)	T: TIM barrels	F: Glu_synthase	ECOD (1.6)
B	Glu_synthase	e1fcbB1	A: a/b barrels	X: TIM beta/alpha-barrel	H: TIM barrels (From Topology)	T: TIM barrels	F: Glu_synthase	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	3.10.120.10	Alpha Beta	Roll	Flavocytochrome B2	Chain A, domain 1	CATH (4.3.0)
A	3.20.20.70	Alpha Beta	Alpha-Beta Barrel	TIM Barrel	Aldolase class I	CATH (4.3.0)
B	3.20.20.70	Alpha Beta	Alpha-Beta Barrel	TIM Barrel	Aldolase class I	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, B	PF01070	FMN-dependent dehydrogenase (FMN_dh)	FMN-dependent dehydrogenase	-	Domain
A, B	PF00173	Cytochrome b5-like Heme/Steroid binding domain (Cyt-b5)	Cytochrome b5-like Heme/Steroid binding domain	This family includes heme binding domains from a diverse range of proteins. This family also includes proteins that bind to steroids. The family includes progesterone receptors such as Swiss:O00264 [1,2]. Many members of this subfamily are membrane a ...	This family includes heme binding domains from a diverse range of proteins. This family also includes proteins that bind to steroids. The family includes progesterone receptors such as Swiss:O00264 [1,2]. Many members of this subfamily are membrane anchored by an N-terminal transmembrane alpha helix. This family also includes a domain in some chitin synthases. There is no known ligand for this domain in the chitin synthases.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, B	FLAVOCYTOCHROME B2	oxidoreductase activity, acting on the CH-OH group of donors, cytochrome as acceptor oxidoreductase activity oxidoreductase activity, acting on CH-OH group of donors L-lactate dehydrogenase (cytochrome) activity lactate dehydrogenase activity catalytic activity binding organic cyclic compound binding tetrapyrrole binding heme binding cation binding ion binding metal ion binding small molecule binding	oxoacid metabolic process organic hydroxy compound metabolic process cellular metabolic process carboxylic acid metabolic process metabolic process small molecule metabolic process cellular process monocarboxylic acid metabolic process organic acid metabolic process lactate metabolic process	membrane-bounded organelle intracellular organelle intracellular anatomical structure mitochondrion organelle cytoplasm cellular anatomical entity intracellular membrane-bounded organelle mitochondrial membrane organelle inner membrane membrane mitochondrial inner membrane organelle envelope mitochondrial envelope membrane-bounded organelle intracellular organelle intracellular anatomical structure mitochondrion organelle cytoplasm cellular anatomical entity intracellular membrane-bounded organelle mitochondrial membrane organelle inner membrane membrane mitochondrial inner membrane organelle envelope mitochondrial envelope organelle membrane cytosol mitochondrial intermembrane space membrane-enclosed lumen intracellular organelle lumen organelle envelope lumen organelle lumen nucleus

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, B	IPR036400	Cytochrome b5-like heme/steroid binding domain superfamily	Homologous Superfamily
A, B	IPR018506	Cytochrome b5, heme-binding site	Binding Site
A, B	IPR037458	L-mandelate/L-lactate dehydrogenase, FMN-binding domain	Domain
A, B	IPR013785	Aldolase-type TIM barrel	Homologous Superfamily
A, B	IPR000262	FMN-dependent dehydrogenase	Domain
A, B	IPR008259	FMN-dependent alpha-hydroxy acid dehydrogenase, active site	Active Site
A, B	IPR001199	Cytochrome b5-like heme/steroid binding domain	Domain
A, B	IPR037396	FMN hydroxy acid dehydrogenase domain	Domain

Structure Motif Annotation: Mechanism and Catalytic Site Atlas M-CSA Database Homepage

Chains	Enzyme Name	Description	Catalytic Residues
A	L-lactate dehydrogenase (cytochrome) M-CSA #102	The flavo-cytochrome enzyme is a lactate dehydrogenase that catalyses the transfer of a hydride equivalent from its hydroxy acid substrate to the enzyme bound flavin, and thence to proteins of the mitochondrial electron transport chain via a bound cytochrome. The enzyme contains two domains, the flavin domain, capable of converting lactate to pyruvate by itself, and the heme domain which contains the prosthetic group involved in electron transfer from the reduced flavin to an acceptor cytochrome.	Defined by 3 residues: TYR:A-254ASP:A-282HIS:A-373 \| Explore in 3D: M-CSA Motif Definition Search M-CSA Motif EC: 1.1.2.3 (PDB Primary Data) Search M-CSA Motif + EC 1.1.2.3

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.