ATP synthase F1 subunit alpha, mitochondrial is an enzyme that in humans is encoded by the ATP5F1A gene. [5] [6]
ATP synthase F1 subunit alpha, mitochondrial is an enzyme that in humans is encoded by the ATP5F1A gene. [5] [6]
This gene encodes a subunit of mitochondrial ATP synthase. Mitochondrial ATP synthase catalyzes ATP synthesis, using an electrochemical gradient of protons across the inner membrane during oxidative phosphorylation. ATP synthase is composed of two linked multi-subunit complexes: the soluble catalytic core, F1, and the membrane-spanning component, Fo, comprising the proton channel. The catalytic portion of mitochondrial ATP synthase consists of 5 different subunits (alpha, beta, gamma, delta, and epsilon) assembled with a stoichiometry of 3 alpha, 3 beta, and a single representative of the other 3. The proton channel consists of three main subunits (a, b, c). This gene encodes the alpha subunit of the catalytic core. Alternatively spliced transcript variants encoding the same protein have been identified. Pseudogenes of this gene are located on chromosomes 9, 2, and 16. [6]
The ATP5F1A gene, located on the q arm of chromosome 18 in position 21, is made up of 13 exons and is 20,090 base pairs in length. [6] The ATP5F1A protein weighs 59.7 kDa and is composed of 553 amino acids. [7] [8] The protein is a subunit of the catalytic portion of the F1Fo ATPase, also known as Complex V, which consists of 14 nuclear and 2 mitochondrial -encoded subunits. As an alpha subunit, ATP5F1A is contained within the catalytic F1 portion of the complex. [6] The nomenclature of the enzyme has a long history. The F1 fraction derives its name from the term "Fraction 1" and Fo (written as a subscript letter "o", not "zero") derives its name from being the binding fraction for oligomycin, a type of naturally-derived antibiotic that is able to inhibit the Fo unit of ATP synthase. [9] [10] The F1 particle is large and can be seen in the transmission electron microscope by negative staining. [11] These are particles of 9 nm diameter that pepper the inner mitochondrial membrane. They were originally called elementary particles and were thought to contain the entire respiratory apparatus of the mitochondrion, but, through a long series of experiments, Efraim Racker and his colleagues (who first isolated the F1 particle in 1961) were able to show that this particle is correlated with ATPase activity in uncoupled mitochondria and with the ATPase activity in submitochondrial particles created by exposing mitochondria to ultrasound. This ATPase activity was further associated with the creation of ATP by a long series of experiments in many laboratories.
Mitochondrial membrane ATP synthase (F1Fo ATP synthase or Complex V) produces ATP from ADP in the presence of a proton gradient across the membrane which is generated by electron transport complexes of the respiratory chain. F-type ATPases consist of two structural domains, F1 - containing the extramembraneous catalytic core, and Fo - containing the membrane proton channel, linked together by a central stalk and a peripheral stalk. During catalysis, ATP synthesis in the catalytic domain of F1 is coupled via a rotary mechanism of the central stalk subunits to proton translocation. Subunits alpha and beta form the catalytic core in F1. Rotation of the central stalk against the surrounding alpha(3)beta(3) subunits leads to hydrolysis of ATP in three separate catalytic sites on the beta subunits. Subunit alpha does not bear the catalytic high-affinity ATP-binding sites. [12]
Mutations affecting the ATP5F1A gene cause combined oxidative phosphorylation deficiency 22 (COXPD22), a mitochondrial disorder characterized by intrauterine growth retardation, microcephaly, hypotonia, pulmonary hypertension, failure to thrive, encephalopathy, and heart failure. Mutations on the ATP5F1A gene also cause mitochondrial complex V deficiency, nuclear 4 (MC5DN4), a mitochondrial disorder with heterogeneous clinical manifestations including dysmorphic features, psychomotor retardation, hypotonia, growth retardation, cardiomyopathy, enlarged liver, hypoplastic kidneys and elevated lactate levels in urine, plasma and cerebrospinal fluid. [13]
Resveratrol inhibition of the F1 catalytic core increases adenosine monophosphate (AMP) levels, thereby activating the AMP-activated protein kinase enzyme. [14]
| Characteristic | Phenotype |
|---|---|
| Homozygote viability | Abnormal |
| Recessive lethal study | Abnormal |
| Body weight | Abnormal [15] |
| Anxiety | Normal |
| Neurological assessment | Normal |
| Grip strength | Normal |
| Hot plate | Normal |
| Dysmorphology | Normal |
| Indirect calorimetry | Normal |
| Glucose tolerance test | Normal |
| Auditory brainstem response | Normal |
| DEXA | Abnormal [16] |
| Radiography | Normal |
| Body temperature | Normal |
| Eye morphology | Normal |
| Clinical chemistry | Abnormal [17] |
| Haematology | Normal |
| Peripheral blood lymphocytes | Normal |
| Micronucleus test | Normal |
| Heart weight | Normal |
| Eye Histopathology | Normal |
| Citrobacter infection | Normal [18] |
| All tests and analysis from [19] [20] |
Model organisms have been used in the study of ATP5F1A function. A conditional knockout mouse line, called Atp5a1tm1a(EUCOMM)Wtsi [21] [22] was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists. [23] [24] [25]
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. [19] [26] Twenty two tests were carried out on mutant mice and five significant abnormalities were observed. [19] No homozygous mutant embryos were identified during gestation, and therefore none survived until weaning. The remaining tests were carried out on heterozygous mutant adult mice and decreased body weight, lean body mass and hypoproteinemia was observed in female animals. [19]
ATP synthase is a protein that catalyzes the formation of the energy storage molecule adenosine triphosphate (ATP) using adenosine diphosphate (ADP) and inorganic phosphate (Pi). ATP synthase is a molecular machine. The overall reaction catalyzed by ATP synthase is:
MT-ATP8 is a mitochondrial gene with the full name 'mitochondrially encoded ATP synthase membrane subunit 8' that encodes a subunit of mitochondrial ATP synthase, ATP synthase Fo subunit 8. This subunit belongs to the Fo complex of the large, transmembrane F-type ATP synthase. This enzyme, which is also known as complex V, is responsible for the final step of oxidative phosphorylation in the electron transport chain. Specifically, one segment of ATP synthase allows positively charged ions, called protons, to flow across a specialized membrane inside mitochondria. Another segment of the enzyme uses the energy created by this proton flow to convert a molecule called adenosine diphosphate (ADP) to ATP. Subunit 8 differs in sequence between Metazoa, plants and Fungi.
MT-ATP6 is a mitochondrial gene with the full name 'mitochondrially encoded ATP synthase membrane subunit 6' that encodes the ATP synthase Fo subunit 6. This subunit belongs to the Fo complex of the large, transmembrane F-type ATP synthase. This enzyme, which is also known as complex V, is responsible for the final step of oxidative phosphorylation in the electron transport chain. Specifically, one segment of ATP synthase allows positively charged ions, called protons, to flow across a specialized membrane inside mitochondria. Another segment of the enzyme uses the energy created by this proton flow to convert a molecule called adenosine diphosphate (ADP) to ATP. Mutations in the MT-ATP6 gene have been found in approximately 10 to 20 percent of people with Leigh syndrome.
ATP synthase F1 subunit beta, mitochondrial is an enzyme that in humans is encoded by the ATP5F1B gene.
ATP synthase-coupling factor 6, mitochondrial is an enzyme subunit that in humans is encoded by the ATP5PF gene.
The ATP5MC1 gene is one of three human paralogs that encode membrane subunit c of the mitochondrial ATP synthase.
The ATP5MF gene encodes the ATP synthase subunit f, mitochondrial enzyme in humans.
The alpha and beta subunits are found in the F1, V1, and A1 complexes of F-, V- and A-ATPases, respectively, as well as flagellar (T3SS) ATPase and the termination factor Rho. The subunits make up a ring that contains the ATP-hydrolyzing catalytic core. The F-ATPases, V-ATPases and A-ATPases are composed of two linked complexes: the F1, V1 or A1 complex containsthat synthesizes/hydrolyses ATP, and the Fo, Vo or Ao complex that forms the membrane-spanning pore. The F-, V- and A-ATPases all contain rotary motors, one that drives proton translocation across the membrane and one that drives ATP synthesis/hydrolysis.
ATP synthase delta subunit is a subunit of bacterial and chloroplast F-ATPase/synthase. It is known as OSCP in mitochondrial ATPase.
ATP synthase subunit g, mitochondrial is an enzyme that in humans is encoded by the ATP5MG gene.
Gamma subunit of ATP synthase F1 complex forms the central shaft that connects the Fo rotary motor to the F1 catalytic core. F-ATP synthases are composed of two linked complexes: the F1 ATPase complex is the catalytic core and is composed of 5 subunits, while the Fo ATPase complex is the membrane-embedded proton channel that is composed of at least 3 subunits (A-C), nine in mitochondria.
The human ATP5F1C gene encodes the gamma subunit of an enzyme called mitochondrial ATP synthase.
ATP synthase subunit b, mitochondrial is an enzyme that in humans is encoded by the ATP5PB gene.
ATP synthase subunit s, mitochondrial is an enzyme that in humans is encoded by the ATP5S gene.
The ATP5MC2 gene is one of three human paralogs that encode membrane subunit c of the mitochondrial ATP synthase.
ATP synthase subunit e, mitochondrial is an enzyme that in humans is encoded by the ATP5ME gene.
The human gene ATP5PD encodes subunit d of the peripheral stalk part of the enzyme mitochondrial ATP synthase.
ATP synthase subunit delta, mitochondrial, also known as ATP synthase F1 subunit delta or F-ATPase delta subunit is an enzyme that in humans is encoded by the ATP5F1D gene. This gene encodes a subunit of mitochondrial ATP synthase. Mitochondrial ATP synthase catalyzes ATP synthesis, utilizing an electrochemical gradient of protons across the inner membrane during oxidative phosphorylation.
ATP synthase F1 subunit epsilon, mitochondrial is an enzyme that in humans is encoded by the ATP5F1E gene. The protein encoded by ATP5F1E is a subunit of ATP synthase, also known as Complex V. Variations of this gene have been associated with mitochondrial complex V deficiency, nuclear 3 (MC5DN3) and Papillary Thyroid Cancer.
The ATP5MC3 gene is one of three human paralogs that encode membrane subunit c of the mitochondrial ATP synthase.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.
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