Reviewed, UniProtKB/Swiss-Prot P20070 (NB5R3_RAT)

Names and origin

Protein names

Recommended name:
    NADH-cytochrome b5 reductase 3
      Short name=Cytochrome b5 reductase
      Short name=B5R
    EC=1.6.2.2
Alternative name(s):
    Diaphorase-1
Cleaved into the following 2 chains:
    1- Recommended name:
            NADH-cytochrome b5 reductase 3 membrane-bound form
    2- Recommended name:
            NADH-cytochrome b5 reductase 3 soluble form

Gene names

Name:	Cyb5r3
Synonyms:	Dia1

Organism

Rattus norvegicus (Rat)

Taxonomic identifier

10116 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Glires › Rodentia › Sciurognathi › Muroidea › Muridae › Murinae › Rattus

Protein attributes

Sequence length	301 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Desaturation and elongation of fatty acids, cholesterol biosynthesis, drug metabolism, and, in erythrocyte, methemoglobin reduction.
Catalytic activity	NADH + 2 ferricytochrome b5 = NAD+ + H+ + 2 ferrocytochrome b5.
Cofactor	FAD.
Subunit structure	Component of a complex composed of cytochrome b5, NADH-cytochrome b5 reductase (CYB5R3) and MOSC2 By similarity.
Subcellular location	Isoform 1: Endoplasmic reticulum membrane; Lipid-anchor; Cytoplasmic side. Mitochondrion outer membrane; Lipid-anchor; Cytoplasmic side. Isoform 3: Cytoplasm. Note: Produces the soluble form found in erythrocytes.
Tissue specificity	Isoform 1 and isoform 3 are ubiquitously expressed. Isoform 2 is expressed only in erythroid tissues, reticulocytes and liver. Ref.4
Post-translational modification	Only the isoform 1 is myristoyled.
Sequence similarities	Belongs to the flavoprotein pyridine nucleotide cytochrome reductase family. Contains 1 FAD-binding FR-type domain.

Ontologies

Keywords
Biological process	Cholesterol biosynthesis Lipid synthesis Steroid biosynthesis Sterol biosynthesis
Cellular component	Cytoplasm Endoplasmic reticulum Membrane Mitochondrion Mitochondrion outer membrane
Coding sequence diversity	Alternative initiation Alternative promoter usage
Ligand	FAD Flavoprotein NAD
Molecular function	Oxidoreductase
PTM	Acetylation Lipoprotein Myristate Phosphoprotein
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological process	cholesterol biosynthetic process Inferred from electronic annotation. Source: UniProtKB-KW oxidation reduction Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	endoplasmic reticulum membrane Inferred from direct assay. Source: HGNC mitochondrial outer membrane Inferred from electronic annotation. Source: UniProtKB-SubCell soluble fraction Ref.1 Traceable author statement. Source: RGD
Molecular function	ADP binding Inferred from direct assay. Source: RGD AMP binding Inferred from direct assay. Source: RGD FAD binding Inferred from direct assay. Source: RGD NAD or NADH binding Inferred from direct assay. Source: RGD cytochrome-b5 reductase activity Ref.1 Traceable author statement. Source: RGD electron carrier activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Alternative products

This entry describes 3 isoforms produced by alternative promoter usage and alternative initiation. [Align] [Select]

Isoform 1 (identifier: P20070-1)

Also known as: L-form reticulocyte reductase;

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

Note: Produced by alternative promoter usage.

Isoform 2 (identifier: P20070-2)

Also known as: R-form reticulocyte reductase;

The sequence of this isoform differs from the canonical sequence as follows:
     1-7: MGAQLST → MLGPLLWTASLPV

Note: Produced by alternative promoter usage.

Isoform 3 (identifier: P20070-3)

Also known as: Soluble form;

The sequence of this isoform differs from the canonical sequence as follows:
     1-23: Missing.

Note: Produces the soluble form found in erythrocytes. Produced by alternative initiation.

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Initiator methionine

1

1

Removed Ref.5

Chain

2 – 301

300

NADH-cytochrome b5 reductase 3 membrane-bound form

PRO_0000019401

Chain

27 – 301

275

NADH-cytochrome b5 reductase 3 soluble form

PRO_0000019403

Regions

Domain

40 – 152

113

FAD-binding FR-type

Nucleotide binding

132 – 147

16

FAD

Nucleotide binding

171 – 206

36

FAD

Amino acid modifications

Modified residue

42

1

N6-acetyllysine By similarity

Modified residue

43

1

Phosphotyrosine By similarity

Modified residue

120

1

N6-acetyllysine By similarity

Modified residue

130

1

Phosphotyrosine By similarity

Lipidation

2

1

N-myristoyl glycine

Natural variations

Alternative sequence

1 – 23

23

Missing in isoform 3.

VSP_009660

Alternative sequence

1 – 7

7

MGAQLST → MLGPLLWTASLPV in isoform 2.

VSP_009661

Experimental info

Sequence conflict

105

1

F → L in AAA41008. Ref.2

Secondary structure

1

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301

Helix Strand Turn

Details...

Beta strand

43 – 54

12

Beta strand

57 – 63

7

Beta strand

78 – 85

8

Beta strand

88 – 94

7

Beta strand

104 – 111

8

Beta strand

115 – 118

4

Helix

126 – 132

7

Beta strand

139 – 146

8

Beta strand

148 – 153

6

Beta strand

156 – 159

4

Beta strand

168 – 171

4

Beta strand

173 – 180

8

Helix

181 – 183

3

Helix

184 – 196

13

Beta strand

203 – 212

10

Helix

213 – 215

3

Helix

219 – 228

10

Helix

230 – 232

3

Beta strand

233 – 241

9

Beta strand

248 – 252

5

Helix

255 – 261

7

Beta strand

269 – 275

7

Helix

277 – 282

6

Helix

285 – 291

7

Helix

295 – 297

3

Beta strand

298 – 300

3

Sequences

	Sequence		Length	Mass (Da)
	Isoform 1 (L-form reticulocyte reductase) [UniParc]. Last modified January 23, 2007. Version 2. Checksum: 45431A644413905F	FASTA	301	34,175
	10 20 30 40 50 60 MGAQLSTLSR VVLSPVWFVY SLFMKLFQRS SPAITLENPD IKYPLRLIDK EIISHDTRRF 70 80 90 100 110 120 RFALPSPQHI LGLPIGQHIY LSTRIDGNLV IRPYTPVSSD DDKGFVDLVV KVYFKDTHPK 130 140 150 160 170 180 FPAGGKMSQY LENMNIGDTI EFRGPNGLLV YQGKGKFAIR ADKKSNPVVR TVKSVGMIAG 190 200 210 220 230 240 GTGITPMLQV IRAVLKDPND HTVCYLLFAN QSEKDILLRP ELEELRNEHS SRFKLWYTVD 250 260 270 280 290 300 KAPDAWDYSQ GFVNEEMIRD HLPPPGEETL ILMCGPPPMI QFACLPNLER VGHPKERCFT F
	Isoform 2 (R-form reticulocyte reductase). Checksum: BEF7A5F4F12AC7C2	FASTA	307	34,866
	10 20 30 40 50 60 MLGPLLWTAS LPVLSRVVLS PVWFVYSLFM KLFQRSSPAI TLENPDIKYP LRLIDKEIIS 70 80 90 100 110 120 HDTRRFRFAL PSPQHILGLP IGQHIYLSTR IDGNLVIRPY TPVSSDDDKG FVDLVVKVYF 130 140 150 160 170 180 KDTHPKFPAG GKMSQYLENM NIGDTIEFRG PNGLLVYQGK GKFAIRADKK SNPVVRTVKS 190 200 210 220 230 240 VGMIAGGTGI TPMLQVIRAV LKDPNDHTVC YLLFANQSEK DILLRPELEE LRNEHSSRFK 250 260 270 280 290 300 LWYTVDKAPD AWDYSQGFVN EEMIRDHLPP PGEETLILMC GPPPMIQFAC LPNLERVGHP KERCFTF
	Isoform 3 (Soluble form). Checksum: 4FA80DCDADD24A1B	FASTA	278	31,592
	10 20 30 40 50 60 MKLFQRSSPA ITLENPDIKY PLRLIDKEII SHDTRRFRFA LPSPQHILGL PIGQHIYLST 70 80 90 100 110 120 RIDGNLVIRP YTPVSSDDDK GFVDLVVKVY FKDTHPKFPA GGKMSQYLEN MNIGDTIEFR 130 140 150 160 170 180 GPNGLLVYQG KGKFAIRADK KSNPVVRTVK SVGMIAGGTG ITPMLQVIRA VLKDPNDHTV 190 200 210 220 230 240 CYLLFANQSE KDILLRPELE ELRNEHSSRF KLWYTVDKAP DAWDYSQGFV NEEMIRDHLP 250 260 270 PPGEETLILM CGPPPMIQFA CLPNLERVGH PKERCFTF

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Molecular cloning of a cDNA encoding rat NADH-cytochrome b5 reductase and the corresponding gene." Zenno S., Hattori M., Misumi Y., Yubisui T., Sakaki Y. J. Biochem. 107:810-816(1990) [PubMed: 2391344] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1). Tissue: Liver.
[2]	"Two transcripts encode rat cytochrome b5 reductase." Pietrini G., Carrera P., Borgese N. Proc. Natl. Acad. Sci. U.S.A. 85:7246-7250(1988) [PubMed: 3174630] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1). Strain: Sprague-Dawley. Tissue: Liver.
[3]	"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)." The MGC Project Team Genome Res. 14:2121-2127(2004) [PubMed: 15489334] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 1). Tissue: Prostate.
[4]	"A single mRNA, transcribed from an alternative, erythroid-specific, promoter, codes for two non-myristylated forms of NADH-cytochrome b5 reductase." Pietrini G., Aggujaro D., Carrera P., Malyszko J., Vitale A., Borgese N. J. Cell Biol. 117:975-986(1992) [PubMed: 1577871] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] OF 1-37 (ISOFORMS 1; 2 AND 3), TISSUE SPECIFICITY. Strain: Sprague-Dawley and Wistar. Tissue: Liver and Reticulocyte.
[5]	"The NH2-terminal structures of human and rat liver microsomal NADH-cytochrome b5 reductases." Murakami K., Yubisui T., Takeshita M., Miyata T. J. Biochem. 105:312-317(1989) [PubMed: 2498303] [Abstract] Cited for: PROTEIN SEQUENCE OF 2-25, MYRISTOYLATION AT GLY-2. Tissue: Liver.
[6]	"Heterogeneity of the rat NADH-cytochrome-b5-reductase transcripts resulting from multiple alternative first exons." Mota Vieira L., Kaplan J.-C., Kahn A., Leroux A. Eur. J. Biochem. 220:729-737(1994) [PubMed: 8143727] [Abstract] Cited for: ALTERNATIVE SPLICING.
[7]	"A role for N-myristoylation in protein targeting: NADH-cytochrome b5 reductase requires myristic acid for association with outer mitochondrial but not ER membranes." Borgese N., Aggujaro D., Carrera P., Pietrini G., Bassetti M. J. Cell Biol. 135:1501-1513(1996) [PubMed: 8978818] [Abstract] Cited for: ROLE OF MYRISTOYLATION.
[8]	"High-level expression in Escherichia coli of the soluble, catalytic domain of rat hepatic cytochrome b5 reductase." Barber M.J., Quinn G.B. Protein Expr. Purif. 8:41-47(1996) [PubMed: 8812833] [Abstract] Cited for: FAD-BINDING.
[9]	"The structure and biochemistry of NADH-dependent cytochrome b5 reductase are now consistent." Bewley M.C., Marohnic C.C., Barber M.J. Biochemistry 40:13574-13582(2001) [PubMed: 11695905] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS) OF 34-301.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBLGenBankDDBJ

D00636 mRNA. Translation: BAA00530.1.
J03867 mRNA. Translation: AAA41008.1.
BC062066 mRNA. Translation: AAH62066.1.
X65191 mRNA. Translation: CAA46308.1.
X65191 mRNA. Translation: CAA46309.1.
X65190 Genomic DNA. Translation: CAA46307.1.
X77117 Genomic DNA. No translation available.

IPI

IPI00231662.
IPI00760146.
IPI00760152.

PIR

RDRTB5. A40495.
S23641.

RefSeq

NP_620232.1.

UniGene

Rn.35994

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1I7P	X-ray	2.00	A	34-301	[»]
1IB0	X-ray	2.30	A	34-301	[»]
1QX4	X-ray	1.80	A/B	34-300	[»]

ModBase

Search...

Proteomic databases

PRIDE

P20070.

Genome annotation databases

Ensembl

ENSRNOG00000009592. Rattus norvegicus. [Contig view]

GeneID

25035.

KEGG

rno:25035.

Organism-specific databases

RGD

2502. Cyb5r3.

Phylogenomic databases

HOVERGEN

P20070.

Enzyme and pathway databases

BRENDA

1.6.2.2. 248.

Gene expression databases

ArrayExpress

P20070.

GermOnline

ENSRNOG00000009592. Rattus norvegicus.

Family and domain databases

InterPro

IPR017927. Fd_Rdtase_FAD-bd.
IPR001709. Flavoprot_Pyr_Nucl_cyt_Rdtase.
IPR001834. NADH-Cyt_B5_reductase.
IPR008333. OxRdtase_FAD-bd.
IPR001433. OxRdtase_FAD/NAD_bd.
[Graphical view]

Pfam

PF00970. FAD_binding_6. 1 hit.
PF00175. NAD_binding_1. 1 hit.
[Graphical view]

PRINTS

PR00406. CYTB5RDTASE.
PR00371. FPNCR.

PROSITE

PS51384. FAD_FR. 1 hit.
[Graphical view]

ProtoNet

Search...

Other Resources

NextBio

605189.

Entry information

Entry name

NB5R3_RAT

Accession

Primary (citable) accession number: P20070
Secondary accession number(s): Q64569, Q64720

Entry history

Integrated into UniProtKB/Swiss-Prot:	February 1, 1991
Last sequence update:	January 23, 2007
Last modified:	June 16, 2009
This is version 104 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HPI (Human Proteome Initiative)