NDUFB7

Gene

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

Structure

The NDUFB7 protein weighs 16.4 kDa and is composed of 137 amino acids. 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 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. 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.

References

References

1. (Nov 1998). "Intron based radiation hybrid mapping of 15 complex I genes of the human electron transport chain". Cytogenetics and Cell Genetics.
2. (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.
3. "Entrez Gene: NDUFB7 NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 7, 18kDa".
4. (2013). "Fundamentals of biochemistry: life at the molecular level". Wiley.
5. (Oct 2013). "Integration of cardiac proteome biology and medicine by a specialized knowledgebase". Circulation Research.
6. "NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 7". Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).
7. (Mar 2011). "NDUFB7 and NDUFA8 are located at the intermembrane surface of complex I". FEBS Letters.