The NDUFA11 gene is located on the p arm of chromosome 19 in position 13.3 and spans 12,738 base pairs.[7] The gene produces a 15 kDa protein composed of 141 amino acids.[8][9] NDUFA11 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.[5] 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. NDUFA11 is one of about 31 hydrophobic subunits that form the transmembrane region of Complex I, but it is an accessory subunit that is believed not to be involved in catalysis.[10] The predicted secondary structure is primarily alpha helix, but the carboxy-terminal half of the protein has high potential to adopt a coiled-coil form. The amino-terminal part contains a putative beta sheet rich in hydrophobic amino acids that may serve as mitochondrial import signal.[6][7][11]
