The NDUFB8 protein weighs 22 kDa and is composed of 186 amino acids.[8][9] NDUFB8 is a subunit of the enzyme NADH dehydrogenase (ubiquinone), the largest of the respiratory complexes. The structure is L-shaped with a long, hydrophobictransmembrane domain and a hydrophilic domain for the peripheral arm that includes all the known redox centers and the NADH binding site.[7]NDUFB7 and NDUFB8 have been shown to localize at the intermembrane surface of complex I.[10] 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.[6]
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.[6] 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.[7]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Emahazion T, Brookes AJ (Nov 1998). "Mapping of the NDUFA2, NDUFA6, NDUFA7, NDUFB8, and NDUFS8 electron transport chain genes by intron based radiation hybrid mapping". Cytogenetics and Cell Genetics. 82 (1–2): 114. doi:10.1159/000015081. PMID9763676. S2CID46861680.
Dunbar DR, Shibasaki Y, Dobbie L, Andersson B, Brookes AJ (1997). "In situ hybridisation mapping of genomic clones for five human respiratory chain complex I genes". Cytogenetics and Cell Genetics. 78 (1): 21–4. doi:10.1159/000134618. PMID9345899.
Loeffen JL, Triepels RH, van den Heuvel LP, Schuelke M, Buskens CA, Smeets RJ, Trijbels JM, Smeitink JA (Dec 1998). "cDNA of eight nuclear encoded subunits of NADH:ubiquinone oxidoreductase: human complex I cDNA characterization completed". Biochemical and Biophysical Research Communications. 253 (2): 415–22. doi:10.1006/bbrc.1998.9786. PMID9878551.
Emahazion T, Jobs M, Howell WM, Siegfried M, Wyöni PI, Prince JA, Brookes AJ (Oct 1999). "Identification of 167 polymorphisms in 88 genes from candidate neurodegeneration pathways". Gene. 238 (2): 315–24. doi:10.1016/S0378-1119(99)00330-3. PMID10570959.
Ma J, Dempsey AA, Stamatiou D, Marshall KW, Liew CC (Mar 2007). "Identifying leukocyte gene expression patterns associated with plasma lipid levels in human subjects". Atherosclerosis. 191 (1): 63–72. doi:10.1016/j.atherosclerosis.2006.05.032. PMID16806233.
Hsieh SM, Maguire DJ, Lintell NA, McCabe M, Griffiths LR (2007). "Pten and Ndufb8 Aberrations in Cervical Cancer Tissue". Oxygen Transport to Tissue XXVIII. Advances in Experimental Medicine and Biology. Vol. 599. pp. 31–6. doi:10.1007/978-0-387-71764-7_5. ISBN978-0-387-71763-0. PMID17727244.
