 |
A maltoside is a glycoside with maltose as the glycone (sugar) functional group. Among the most common are alkyl maltosides, which contain hydrophobic alkyl chains as the aglycone. Given their amphiphilic properties, these comprise a class of detergents, where variation in the alkyl chain confers a range of detergent properties including CMC and solubility. Maltosides are most often used for the solubilization and purification of membrane proteins.
In 1980 Ferguson-Miller et al. at Michigan State developed n-dodecyl-β-D-maltopyranoside (DDM) as part of a successful effort to purify an active, stable, monodisperse form of cytochrome c oxidase. [1] Maltosides have been used extensively to stabilize membrane proteins for biophysical and structural studies.
| Maltoside | abbr. | CMC (mM) | MW (g/mol) | Micelle (kDa) |
|---|---|---|---|---|
| n-Decyl-β-D-maltopyranoside | DM | 1.8 [2] (H2O) | 482.6 | ~33 (69 molecules) [3] |
| n-Dodecyl-β-D-maltopyranoside | DDM | 0.17 [4] | 510.6 | ~72 (~78-149 molecules) [5] |
| 6-Cyclohexyl-1-hexyl-β-D-maltopyranoside | Cymal-6 | 0.56 | 508.5 | 46.3 |
Oxidative phosphorylation or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy in order to produce adenosine triphosphate (ATP). In eukaryotes, this takes place inside mitochondria. Almost all aerobic organisms carry out oxidative phosphorylation. This pathway is so pervasive because it releases more energy than alternative fermentation processes such as anaerobic glycolysis.
An electron transport chain (ETC) is a series of protein complexes and other molecules that transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples this electron transfer with the transfer of protons (H+ ions) across a membrane. The electrons that are transferred from NADH and FADH2 to the ETC involves four multi-subunit large enzymes complexes and two mobile electron carriers. Many of the enzymes in the electron transport chain are embedded within the membrane.
The cytochrome complex, or cyt c, is a small hemeprotein found loosely associated with the inner membrane of the mitochondrion where it plays a critical role in cellular respiration. It transfers electrons between Complexes III and IV. Cytochrome c is highly water-soluble, unlike other cytochromes. It is capable of undergoing oxidation and reduction as its iron atom converts between the ferrous and ferric forms, but does not bind oxygen. It also plays a major role in cell apoptosis. In humans, cytochrome c is encoded by the CYCS gene.
The enzyme cytochrome c oxidase or Complex IV, is a large transmembrane protein complex found in bacteria, archaea, and mitochondria of eukaryotes.
Heme, or haem, is a precursor to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver.
A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta-barrels) can be also extracted using denaturing agents.
n-Octyl β-d-thioglucopyranoside is a mild nonionic detergent that is used for cell lysis or to solubilise membrane proteins without denaturing them. This is particularly of use in order to crystallise them or to reconstitute them into lipid bilayers. It has a critical micelle concentration of 9 mM.
Rieske proteins are iron–sulfur protein (ISP) components of cytochrome bc1 complexes and cytochrome b6f complexes and are responsible for electron transfer in some biological systems. John S. Rieske and co-workers first discovered the protein and in 1964 isolated an acetylated form of the bovine mitochondrial protein. In 1979 Trumpower's lab isolated the "oxidation factor" from bovine mitochondria and showed it was a reconstitutively-active form of the Rieske iron-sulfur protein
It is a unique [2Fe-2S] cluster in that one of the two Fe atoms is coordinated by two histidine residues rather than two cysteine residues. They have since been found in plants, animals, and bacteria with widely ranging electron reduction potentials from -150 to +400 mV.
The inner mitochondrial membrane (IMM) is the mitochondrial membrane which separates the mitochondrial matrix from the intermembrane space.
Polyphosphazenes include a wide range of hybrid inorganic-organic polymers with a number of different skeletal architectures with the backbone P-N-P-N-P-N-. In nearly all of these materials two organic side groups are attached to each phosphorus center. Linear polymers have the formula (N=PR1R2)n, where R1 and R2 are organic (see graphic). Other architectures are cyclolinear and cyclomatrix polymers in which small phosphazene rings are connected together by organic chain units. Other architectures are available, such as block copolymer, star, dendritic, or comb-type structures. More than 700 different polyphosphazenes are known, with different side groups (R) and different molecular architectures. Many of these polymers were first synthesized and studied in the research group of Harry R. Allcock.
Heme A is a heme, a coordination complex consisting of a macrocyclic ligand called a porphyrin, chelating an iron atom. Heme A is a biomolecule and is produced naturally by many organisms. Heme A, often appears a dichroic green/red when in solution, is a structural relative of heme B, a component of hemoglobin, the red pigment in blood.
The alternative oxidase (AOX) is an enzyme that forms part of the electron transport chain in mitochondria of different organisms. Proteins homologous to the mitochondrial oxidase and the related plastid terminal oxidase have also been identified in bacterial genomes.
Cytochrome c oxidase subunit 4 isoform 1, mitochondrial (COX4I1) is an enzyme that in humans is encoded by the COX4I1 gene. COX4I1 is a nuclear-encoded isoform of cytochrome c oxidase (COX) subunit 4. Cytochrome c oxidase is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane, acting as the terminal enzyme of the mitochondrial respiratory chain. Antibodies against COX4 can be used to identify the inner membrane of mitochondria in immunofluorescence studies. Mutations in COX4I1 have been associated with COX deficiency and Fanconi anemia.
Cytochrome c oxidase subunit 5B, mitochondrial is an enzyme in humans that is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. In humans, cytochrome c oxidase subunit 5B is encoded by the COX5B gene.
Cytochrome c oxidase subunit 6A1, mitochondrial is a protein that in humans is encoded by the COX6A1 gene. Cytochrome c oxidase 6A1 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. A mutation of the COX6A1 gene is associated with a recessive axonal or mixed form of Charcot-Marie-Tooth disease.
Cytochrome c oxidase subunit 7B, mitochondrial (COX7B) is an enzyme that in humans is encoded by the COX7B gene. COX7B is a nuclear-encoded subunit of cytochrome c oxidase (COX). Cytochrome c oxidase is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane, acting as the terminal enzyme of the mitochondrial respiratory chain. Work with Oryzias latices has linked disruptions in COX7B with microphthalmia with linear skin lesions (MLS), microcephaly, and mitochondrial disease. Clinically, mutations in COX7B have been associated with linear skin defects with multiple congenital anomalies.
Octyl glucoside is a nonionic surfactant frequently used to solubilise integral membrane proteins for studies in biochemistry. Structurally, it is a glycoside derived from glucose and octanol. Like Genapol X-100 and Triton X-100, it is a nonphysiological amphiphile that makes lipid bilayers less "stiff".
Cytochrome d, previously known as cytochrome a2, is a name for all cytochromes that contain heme D as a cofactor. Two unrelated classes of cytochrome d are known: Cytochrome bd, an enzyme that generates a charge across the membrane so that protons will move, and cytochrome cd1, a nitrite reductase.
Cytochrome c oxidase subunit VIa polypeptide 2 is a protein that in humans is encoded by the COX6A2 gene. Cytochrome c oxidase 6A2 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain.
NDUFA4, mitochondrial complex associated is a protein that in humans is encoded by the NDUFA4 gene. The NDUFA4 protein was first described to be 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. However, recent research has described NDUFA4 as a subunit of cytochrome c oxidase. Mutations in the NDUFA4 gene are associated with Leigh's syndrome.
{{cite journal}}: CS1 maint: multiple names: authors list (link){{cite book}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link)