NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 9 is an enzyme that in humans is encoded by the NDUFB9 gene. [5] [6] NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 9 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. [7]
The NDUFB9 gene is located on the q arm of chromosome 8 in position 13.3 and is 10,884 base pairs long. The NDUFB9 protein weighs 22 kDa and is composed of 179 amino acids. [8] [9] NDUFB9 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. [7] 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]
A mutation in NDUFB9 resulting in reduction in NDUFB9 protein and both amount and activity of complex I has been shown to be a causal mutation leading to Complex I deficiency. [10]
Respiratory complex I, EC 7.1.1.2 is the first large protein complex of the respiratory chains of many organisms from bacteria to humans. It catalyzes the transfer of electrons from NADH to coenzyme Q10 (CoQ10) and translocates protons across the inner mitochondrial membrane in eukaryotes or the plasma membrane of bacteria.
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 5 is an enzyme that in humans is encoded by the NDUFA5 gene. The NDUFA5 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 6, also known as complex I-B17, is a protein that in humans is encoded by the NDUFB6 gene. NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 6, 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.
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 8, mitochondrial is an enzyme that in humans is encoded by the NDUFB8 gene. NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 8 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.
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 6 is an enzyme that in humans is encoded by the NDUFA6 gene. The NDUFA6 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 2 is a protein that in humans is encoded by the NDUFA2 gene. The NDUFA2 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Mutations in the NDUFA2 gene are associated with Leigh's syndrome.
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9 is an enzyme that in humans is encoded by the NDUFA9 gene. The NDUFA9 protein is a subunit of NADH:ubiquinone oxidoreductase, which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Mutations in NADH dehydrogenase (ubiquinone), also known as Complex I, frequently lead to complex neurodegenerative diseases such as Leigh's syndrome. In the case of NDUFA9, a mutation to the MT-ND3 gene might interrupt their interaction and formation of subcomplexes, compromising Complex I function and leading to disease.
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 8 is an enzyme that in humans is encoded by the NDUFA8 gene. The NDUFA8 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 12 is an enzyme that in humans is encoded by the NDUFA12 gene. The NDUFA12 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Mutations in subunits of NADH dehydrogenase (ubiquinone), also known as Complex I, frequently lead to complex neurodegenerative diseases such as Leigh's syndrome that result from mitochondrial complex I deficiency.
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 10 is an enzyme that in humans is encoded by the NDUFA10 gene. The NDUFA10 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Mutations in subunits of NADH dehydrogenase (ubiquinone), also known as Complex I, frequently lead to complex neurodegenerative diseases such as Leigh's syndrome. Furthermore, reduced NDUFA10 expression levels due to FOXM1-directed hypermethylation are associated with human squamous cell carcinoma and may be related to other forms of cancer.
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 1 is an enzyme that in humans is encoded by the NDUFB1 gene. NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 1, 7kDa 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.
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 2, mitochondrial is an enzyme that in humans is encoded by the NDUFB2 gene. 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.
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 7, also known as complex I-B18, is an enzyme that in humans is encoded by the NDUFB7 gene. NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 7 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.
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 10 is an enzyme that in humans is encoded by the NDUFB10 gene. NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 10 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.
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 11, mitochondrial is an enzyme that in humans is encoded by the NDUFB11 gene. NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 11 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. NDUFB11 mutations have been associated with linear skin defects with multiple congenital anomalies 3 and mitochondrial complex I deficiency.
NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 3, 12kDa is a protein that in humans is encoded by the NDUFB3 gene. NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 3, 12kDa 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. Mutations in this gene contribute to mitochondrial complex I deficiency.
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 7 is an enzyme that in humans is encoded by the NDUFA7 gene. The NDUFA7 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 11 is an enzyme that in humans is encoded by the NDUFA11 gene. The NDUFA11 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain Mutations in subunits of NADH dehydrogenase (ubiquinone), also known as Complex I, frequently lead to complex neurodegenerative diseases such as Leigh's syndrome. Mutations in this gene are associated with severe mitochondrial complex I deficiency.
NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 4, 15kDa is a protein that in humans is encoded by the NDUFB4 gene. The NDUFB4 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.
NADH dehydrogenase (ubiquinone) 1 beta subcomplex, 5, 16kDa is a protein that in humans is encoded by the NDUFB5 gene. The NDUFB5 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.
