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AliasesNDUFB7, B18, CI-B18, NADH:ubiquinone oxidoreductase subunit B7
External IDsOMIM: 603842 MGI: 1914166 HomoloGene: 3059 GeneCards: NDUFB7
Gene location (Human)
Chromosome 19 (human)
Chr.Chromosome 19 (human)[1]
Chromosome 19 (human)
Genomic location for NDUFB7
Genomic location for NDUFB7
Band19p13.12Start14,566,078 bp[1]
End14,572,066 bp[1]
RNA expression pattern
PBB GE NDUFB7 202839 s at fs.png
More reference expression data
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 19: 14.57 – 14.57 MbChr 8: 83.57 – 83.57 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 7, also known as complex I-B18, is an enzyme that in humans is encoded by the NDUFB7 gene.[5][6][7] NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 7 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.[8]


The NDUFB7 gene is located on the p arm of chromosome 19 in position 13.12 and is 6,000 base pairs long.[9][10]


The NDUFB7 protein weighs 16.4 kDa and is composed of 137 amino acids.[9][10] NDUFB7 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.[8] NDUFB7 and NDUFB8 have been shown to localize at the intermembrane surface of complex I.[11] 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.[7]


The protein encoded by this gene is an accessory subunit of the multisubunit NADH:ubiquinone oxidoreductase (complex I) that is not directly involved in catalysis. Mammalian complex I is composed of 45 different subunits. It locates at the mitochondrial inner membrane. This protein complex has NADH dehydrogenase activity and oxidoreductase activity. It transfers electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone. Alternative splicing occurs at this locus and two transcript variants encoding distinct isoforms have been identified.[7] 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.[8]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000099795 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000033938 - 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. ^ Emahazion T, Beskow A, Gyllensten U, Brookes AJ (Nov 1998). "Intron based radiation hybrid mapping of 15 complex I genes of the human electron transport chain". Cytogenetics and Cell Genetics. 82 (1–2): 115–9. doi:10.1159/000015082. PMID 9763677.
  6. ^ Triepels R, Smeitink J, Loeffen J, Smeets R, Trijbels F, van den Heuvel L (Apr 2000). "Characterization of the human complex I NDUFB7 and 17.2-kDa cDNAs and mutational analysis of 19 genes of the HP fraction in complex I-deficient-patients". Human Genetics. 106 (4): 385–91. doi:10.1007/s004390000278. PMID 10830904.
  7. ^ a b c "Entrez Gene: NDUFB7 NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 7, 18kDa".
  8. ^ a b c 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.
  9. ^ a b 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.
  10. ^ a b "NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 7". Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).
  11. ^ Szklarczyk R, Wanschers BF, Nabuurs SB, Nouws J, Nijtmans LG, Huynen MA (Mar 2011). "NDUFB7 and NDUFA8 are located at the intermembrane surface of complex I". FEBS Letters. 585 (5): 737–43. doi:10.1016/j.febslet.2011.01.046. PMID 21310150.

Further reading[edit]

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