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C-type Cytochrome
Cytochromes ''c'' (cyt ''c'', c-type cytochromes) cytochromes, or heme-containing proteins, that have heme C Covalent bond, covalently attached to the peptide backbone via one or two thioether bonds. These bonds are in most cases part of a specific Cysteine, Cys-X-X-Cys-Histidine, His (CXXCH) Conserved sequence, binding motif, where X denotes a miscellaneous amino acid. Two thioether bonds of cysteine residues bind to the Vinyl group, vinyl sidechains of heme, and the histidine residue coordinates one Jahn–Teller effect#Coordination chemistry, axial binding site of the heme iron. Less common binding motifs can include a single thioether linkage, a lysine or a methionine instead of the axial histidine or a CXnCH binding motif with n>2. The second axial site of the iron can be coordinated by amino acids of the protein, Substrate (chemistry), substrate molecules or water. Cytochromes ''c'' possess a wide range of properties and function as electron transfer proteins or Catalysis, cat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalysis
Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. The rate increase occurs because the catalyst allows the reaction to occur by an alternative mechanism which may be much faster than the noncatalyzed mechanism. However the noncatalyzed mechanism does remain possible, so that the total rate (catalyzed plus noncatalyzed) can only increase in the presence of the catalyst and never decrease. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhodospirillum Rubrum
''Rhodospirillum rubrum'' (''R. rubrum'') is a Gram-negative, pink-coloured bacterium, with a size of 0.8-1 μm. It is a facultative anaerobe with a large set of possible metabolisms depending on the conditions of its environment. It's capable of using oxygen for aerobic respiration under aerobic conditions, or an alternative terminal electron acceptor for anaerobic respiration under anaerobic conditions. Alternative terminal electron acceptors for ''R. rubrum'' include dimethyl sulfoxide or trimethylamine oxide. Under aerobic growth photosynthesis is genetically suppressed and ''R. rubrum'' is then colorless. After the exhaustion of oxygen, ''R. rubrum'' immediately starts the production of photosynthesis apparatus including membrane proteins, bacteriochlorophylls and carotenoids, i.e. the bacterium becomes photosynthesis active. The repression mechanism for the photosynthesis is poorly understood. The photosynthesis of ''R. rubrum'' differs from that of plants as it possesses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhodopila Globiformis
''Rhodopila globiformis'' is a species of bacteria, formerly known as ''Rhodopseudomonas globiformis''. It is a motile, spherical organism. Cells can grow between 1.6 and 1.8 μm in diameter. The photopigments consist of bacteriochlorophyll aP and aliphatic methoxylated ketocarotenoids. The organism grows under anaerobic conditions in the light or under microaerophilic conditions in the dark. Biotin, p-aminobenzoic acid and a source of reduced sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ... are required as growth factors in order to cultivate this bacteria. This bacteria possesses a high potential cytochrome c2. References Further reading * *Belova, Svetlana E.; Pankratov, Timofei A.; Detkova, Ekaterina N.; Kaparullina, Elena N.; Dedysh, Svetlana N. (July 20, 200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prokaryote
A prokaryote (; less commonly spelled procaryote) is a unicellular organism, single-celled organism whose cell (biology), cell lacks a cell nucleus, nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Ancient Greek (), meaning 'before', and (), meaning 'nut' or 'kernel'. In the earlier two-empire system arising from the work of Édouard Chatton, prokaryotes were classified within the empire Prokaryota. However, in the three-domain system, based upon molecular phylogenetics, prokaryotes are divided into two domain (biology), domains: Bacteria and Archaea. A third domain, Eukaryote, Eukaryota, consists of organisms with nuclei. Prokaryotes evolution, evolved before eukaryotes, and lack nuclei, mitochondria, and most of the other distinct organelles that characterize the eukaryotic cell. Some unicellular prokaryotes, such as cyanobacteria, form colony (biology), colonies held together by biofilms, and large colonies can create multilayered microbial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of Outline of life forms, life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal Kingdom (biology), kingdom Asgard (Archaea), Promethearchaeati and its sole phylum Promethearchaeota. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as Flagellated cell, flagellated cells. The leading evolutiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Helix
An alpha helix (or α-helix) is a sequence of amino acids in a protein that are twisted into a coil (a helix). The alpha helix is the most common structural arrangement in the Protein secondary structure, secondary structure of proteins. It is also the most extreme type of local structure, and it is the local structure that is most easily predicted from a sequence of amino acids. The alpha helix has a right-handed helix conformation in which every backbone amino, N−H group hydrogen bonds to the backbone carbonyl, C=O group of the amino acid that is four residue (biochemistry), residues earlier in the protein sequence. Other names The alpha helix is also commonly called a: * Pauling–Corey–Branson α-helix (from the names of three scientists who described its structure) * 3.613-helix because there are 3.6 amino acids in one ring, with 13 atoms being involved in the ring formed by the hydrogen bond (starting with amidic hydrogen and ending with carbonyl oxygen) Discovery ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methionine
Methionine (symbol Met or M) () is an essential amino acid in humans. As the precursor of other non-essential amino acids such as cysteine and taurine, versatile compounds such as SAM-e, and the important antioxidant glutathione, methionine plays a critical role in the metabolism and health of many species, including humans. Methionine is also involved in angiogenesis and various processes related to DNA transcription, epigenetic expression, and gene regulation. Methionine was first isolated in 1921 by John Howard Mueller. It is Genetic code, encoded by the codon AUG. It was named by Satoru Odake in 1925, as an abbreviation of its structural description 2-amino-4-(methylthio)butanoic acid. Biochemical details Methionine (abbreviated as Met or M; encoded by the codon AUG) is an α-amino acid that is used in the biosynthesis of proteins. It contains a carboxyl group (which is in the deprotonated −COO− form under biological pH conditions), an amino group (which is in the proton ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-terminus
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amine group is bonded to the carboxylic group of another amino acid, making it a chain. That leaves a free carboxylic group at one end of the peptide, called the C-terminus, and a free amine group on the other end called the N-terminus. By convention, peptide sequences are written N-terminus to C-terminus, left to right (in LTR writing systems). This correlates the translation direction to the text direction, because when a protein is translated from messenger RNA, it is created from the N-terminus to the C-terminus, as amino acids are added to the carboxyl end of the protein. Chemistry Each amino acid has an amine group and a carboxylic group. Amino acids link to one another by peptide bonds which form through a dehydration reaction that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spin States (d Electrons)
Spin states when describing transition metal coordination complexes refers to the potential spin configurations of the central metal's d electrons. For several oxidation states, metals can adopt high-spin and low-spin configurations. The ambiguity only applies to first row metals, because second- and third-row metals are invariably low-spin. These configurations can be understood through the two major models used to describe coordination complexes; crystal field theory and ligand field theory (a more advanced version based on molecular orbital theory). High-spin vs. low-spin Octahedral complexes The Ligand-field splitting parameter, Δ splitting of the Atomic orbital, ''d'' orbitals plays an important role in the electron spin state of a coordination complex. Three factors affect Δ: the period (row in periodic table) of the metal ion, the charge of the metal ion, and the field strength of the complex's ligands as described by the spectrochemical series. Only octahedral co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Mass Unit
The dalton or unified atomic mass unit (symbols: Da or u, respectively) is a unit of mass defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. It is a non-SI unit accepted for use with SI. The word "unified" emphasizes that the definition was accepted by both IUPAP and IUPAC. The atomic mass constant, denoted , is defined identically. Expressed in terms of , the atomic mass of carbon-12: . Its value in SI units is an experimentally determined quantity. The 2022 CODATA recommended value of the atomic mass constant expressed in the SI base unit kilogram is:This value serves as a conversion factor of mass from daltons to kilograms, which can easily be converted to grams and other metric units of mass. The 2019 revision of the SI redefined the kilogram by fixing the value of the Planck constant (), improving the precision of the atomic mass constant expressed in SI units by anchoring it to fixed physica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Mass
The molecular mass () is the mass of a given molecule, often expressed in units of daltons (Da). Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. The derived quantity relative molecular mass is the unitless ratio of the mass of a molecule to the atomic mass constant (which is equal to one dalton). The molecular mass and relative molecular mass are distinct from but related to the ''molar mass''. The molar mass is defined as the mass of a given substance divided by the amount of the substance, and is expressed in grams per mole (g/mol). That makes the molar mass an ''average'' of many particles or molecules (weighted by abundance of the isotopes), and the molecular mass the mass of one specific particle or molecule. The molar mass is usually the more appropriate quantity when dealing with macroscopic (weigh-able) quantities of a substance. The definition of molecular weight is most authoritat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
