NDUFB2

NDUFB2
Identifiers
Aliases	NDUFB2, AGGG, CI-AGGG, NADH:ubiquinone oxidoreductase subunit B2
External IDs	MGI: 1915448 HomoloGene: 3341 GeneCards: NDUFB2
Gene ontology Molecular function • NADH dehydrogenase (ubiquinone) activity Cellular component • mitochondrial inner membrane • mitochondrial respiratory chain complex I • respiratory chain • membrane • mitochondrion Biological process • oxidation-reduction process • mitochondrial respiratory chain complex I assembly • mitochondrial electron transport, NADH to ubiquinone Sources:Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	4708	68198
Ensembl	ENSG00000090266	ENSMUSG00000002416
UniProt	O95178	Q9CPU2
RefSeq (mRNA)	NM_004546	NM_026612
RefSeq (protein)	NP_004537.1	NP_080888.1
Location (UCSC)	Chr 7: 140.69 – 140.72 Mb	Chr 6: 39.59 – 39.6 Mb
PubMed search	[1]	[2]
Wikidata

NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 2, mitochondrial is an enzyme that in humans is encoded by the NDUFB2 gene.^[3][4][5] NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 2, 8kDa is an accessory subunit of the NADH dehydrogenase (ubiquinone) complex, located in the mitochondrial inner membrane. It is also known as Complex I and is the largest of the five complexes of the electron transport chain.^[6]

Structure

The NDUFB2 gene, located on the q arm of chromosome 7 in position 34, is 9,966 base pairs long and is composed of 4 exons.^[5] The NDUFB2 protein weighs 8 kDa and is composed of 105 amino acids.^[7][8] NDUFB2 is a subunit of the enzyme NADH dehydrogenase (ubiquinone), the largest of the respiratory complexes. The structure is L-shaped with a long, hydrophobic transmembrane domain and a hydrophilic domain for the peripheral arm that includes all the known redox centers and the NADH binding site.^[6] NDUFB3 is one of about 31 hydrophobic subunits that form the transmembrane region of Complex I. It has been noted that the N-terminal hydrophobic domain has the potential to be folded into an alpha helix spanning the inner mitochondrial membrane with a C-terminal hydrophilic domain interacting with globular subunits of Complex I. The highly conserved two-domain structure suggests that this feature is critical for the protein function and that the hydrophobic domain acts as an anchor for the NADH dehydrogenase (ubiquinone) complex at the inner mitochondrial membrane. Hydropathy analysis revealed that this subunit and 4 other subunits have an overall hydrophilic pattern, even though they are found within the hydrophobic protein (HP) fraction of complex I.^[5]

Function

The human NDUFB2 gene codes for a subunit of Complex I of the respiratory chain, which transfers electrons from NADH to ubiquinone.^[5] However, NDUFB2 is an accessory subunit of the complex that is believed not to be involved in catalysis.^[9] Initially, NADH binds to Complex I and transfers two electrons to the isoalloxazine ring of the flavin mononucleotide (FMN) prosthetic arm to form FMNH₂. The electrons are transferred through a series of iron-sulfur (Fe-S) clusters in the prosthetic arm and finally to coenzyme Q10 (CoQ), which is reduced to ubiquinol (CoQH₂). The flow of electrons changes the redox state of the protein, resulting in a conformational change and pK shift of the ionizable side chain, which pumps four hydrogen ions out of the mitochondrial matrix.^[6]

References

Further reading

This article incorporates text from the United States National Library of Medicine, which is in the public domain.