NDUFB5

NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 5, 16kDa is a protein that in humans is encoded by the NDUFB5 gene.[5] 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.[6]

NDUFB5
Identifiers
AliasesNDUFB5, CISGDH, SGDH, NADH:ubiquinone oxidoreductase subunit B5
External IDsOMIM: 603841 MGI: 1913296 HomoloGene: 31093 GeneCards: NDUFB5
Gene location (Human)
Chr.Chromosome 3 (human)[1]
Band3q26.33Start179,604,690 bp[1]
End179,627,647 bp[1]
Orthologs
SpeciesHumanMouse
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 MbChr 3: 32.74 – 32.75 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

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.[7][8] 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.[6] 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.[5]

Function

The human NDUFB5 gene codes for a subunit of Complex I of the respiratory chain, which transfers electrons from NADH to ubiquinone.[5] However, NDUFB5 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
  1. GRCh38: Ensembl release 89: ENSG00000136521 - Ensembl, May 2017
  2. GRCm38: Ensembl release 89: ENSMUSG00000027673 - Ensembl, May 2017
  3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. "Entrez Gene: NDUFB5 NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 5, 16kDa".
  6. Voet D, Voet JG, Pratt CW (2013). "Chapter 18". Fundamentals of biochemistry: life at the molecular level (4th ed.). Hoboken, NJ: Wiley. pp. 581–620. ISBN 978-0-470-54784-7.
  7. Zong NC, Li H, Li H, Lam MP, Jimenez RC, Kim CS, Deng N, Kim AK, Choi JH, Zelaya I, Liem D, Meyer D, Odeberg J, Fang C, Lu HJ, Xu T, Weiss J, Duan H, Uhlen M, Yates JR, Apweiler R, Ge J, Hermjakob H, Ping P (Oct 2013). "Integration of cardiac proteome biology and medicine by a specialized knowledgebase". Circulation Research. 113 (9): 1043–53. doi:10.1161/CIRCRESAHA.113.301151. PMC 4076475. PMID 23965338.
  8. "NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 5". Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).
  9. "NDUFB5 - NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 5". UniProt: a hub for protein information. The UniProt Consortium. Retrieved 2 April 2015.
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