MT-ND5 is located in mitochondrial DNA from base pair 12,337 to 14,148.[5] The MT-ND5 gene produces a 67 kDa protein composed of 603 amino acids.[9][10] MT-ND5 is one of seven mitochondrial genes encoding subunits of the enzyme
NADH dehydrogenase (ubiquinone), together with
MT-ND1,
MT-ND2,
MT-ND3,
MT-ND4,
MT-ND4L, and
MT-ND6. Also known as
Complex I, this enzyme is 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 centres and the NADH binding site. MT-ND5 and the rest of the mitochondrially encoded subunits are the most hydrophobic of the subunits of Complex I and form the core of the transmembrane region.[6]
Function
The MT-ND5 product is a subunit of the respiratory chain
Complex I that is supposed to belong to the minimal assembly of core proteins required to catalyze
NADH dehydrogenation and
electron transfer to
ubiquinone (coenzyme Q10).[11] 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]
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abcVoet D, Voet JG, Pratt CW (2013). "18". Fundamentals of biochemistry : life at the molecular level (4th ed.). Hoboken, NJ: Wiley. pp. 581–620.
ISBN978-0-470-54784-7.
^
abEl-Hattab, A. W.; Almannai, M.; Scaglia, F.; Adam, M. P.; Ardinger, H. H.; Pagon, R. A.; Wallace, S. E.; Bean LJH; Stephens, K.; Amemiya, A. (1993).
"MELAS". GeneReviews.
PMID20301411.
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ab"MT-ND5". Genetics Home Reference. US National Library of Medicine. Retrieved 23 March 2015.