NDUFB2

NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 2, 8kDa
Identifiers
Symbols NDUFB2 ; AGGG; CI-AGGG
External IDs OMIM: 603838 MGI: 1915448 HomoloGene: 3341 GeneCards: NDUFB2 Gene
EC number 1.6.5.3, 1.6.99.3
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 NP_080888
Location (UCSC) Chr 7:
140.69 – 140.72 Mb		 Chr 6:
39.59 – 39.6 Mb
PubMed search

NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 2, mitochondrial is an enzyme that in humans is encoded by the NDUFB2 gene.[1][2][3] 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.[4]

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.[3] The NDUFB2 protein weighs 8 kDa and is composed of 105 amino acids.[5][6] 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.[4] 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.[3]

Function

The human NDUFB2 gene codes for a subunit of Complex I of the respiratory chain, which transfers electrons from NADH to ubiquinone.[3] However, NDUFB2 is an accessory subunit of the complex that is believed not to be involved in catalysis.[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.[4]

References

  1. ↑ 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". Cytogenet Cell Genet 82 (1–2): 115–9. doi:10.1159/000015082. PMID 9763677.
  2. ↑ Loeffen JL, Triepels RH, van den Heuvel LP, Schuelke M, Buskens CA, Smeets RJ, Trijbels JM, Smeitink JA (Jan 1999). "cDNA of eight nuclear encoded subunits of NADH:ubiquinone oxidoreductase: human complex I cDNA characterization completed". Biochem Biophys Res Commun 253 (2): 415–22. doi:10.1006/bbrc.1998.9786. PMID 9878551.
  3. 1 2 3 4 "Entrez Gene: NDUFB2 NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 2, 8kDa".
  4. 1 2 3 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.
  5. ↑ 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.
  6. ↑ "NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 1". Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).
  7. ↑ "NDUFB2 - NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 2". UniProt: a hub for protein information. The UniProt Consortium. Retrieved 2 April 2015.

Further reading

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

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