NDUFB5

NDUFB5
Identifiers
Aliases	NDUFB5, CISGDH, SGDH, NADH:ubiquinone oxidoreductase subunit B5
External IDs	OMIM: 603841; MGI: 1913296; HomoloGene: 31093; GeneCards: NDUFB5; OMA:NDUFB5 - orthologs
Gene location (Human) Chr. Chromosome 3 (human) Band 3q26.33 Start 179,604,690 bp End 179,627,647 bp
Gene location (Mouse) Chr. Chromosome 3 (mouse) Band 3|3 A3 Start 32,791,139 bp End 32,805,715 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in right ventricle biceps brachii Skeletal muscle tissue of biceps brachii retinal pigment epithelium left ventricle right auricle triceps brachii muscle vastus lateralis muscle right adrenal cortex muscle of thigh Top expressed in plantaris muscle intercostal muscle extensor digitorum longus muscle cardiac muscle tissue of left ventricle interventricular septum facial motor nucleus Ileal epithelium atrioventricular valve endocardial cushion soleus muscle More reference expression data BioGPS n/a
Gene ontology Molecular function NADH dehydrogenase (ubiquinone) activity Cellular component integral component of membrane mitochondrial inner membrane mitochondrial respiratory chain complex I respirasome membrane mitochondrion nucleoplasm Biological process mitochondrial electron transport, NADH to ubiquinone mitochondrial respiratory chain complex I assembly Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 4711 66046 Ensembl ENSG00000136521 ENSMUSG00000027673 UniProt O43674 Q9CQH3 RefSeq (mRNA) NM_002492 NM_001199957 NM_001199958 NM_025316 RefSeq (protein) NP_001186886 NP_001186887 NP_002483 NP_001186887.1 NP_079592 Location (UCSC) Chr 3: 179.6 – 179.63 Mb Chr 3: 32.79 – 32.81 Mb PubMed search
Wikidata
View/Edit Human View/Edit Mouse

NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 5, 16kDa is a protein that in humans is encoded by the NDUFB5 gene. The NDUFB5 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.

Structure

The NDUFB5 gene, located on the q arm of chromosome 3 in position 26.33, is 19,713 base pairs long. The NDUFB5 protein weighs 21.7 kDa and is composed of 189 amino acids. NDUFB5 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. NDUFB5 is one of about 31 hydrophobic subunits that form the transmembrane region of Complex I and is of the non-catalytic subunits of the complex. 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.

Function

The human NDUFB5 gene codes for a subunit of Complex I of the respiratory chain, which transfers electrons from NADH to ubiquinone. However, NDUFB5 is an accessory subunit of the complex that is believed not to be involved in catalysis. 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.