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Phage-assisted Continuous Evolution
Phage-assisted continuous evolution (PACE) is a phage-based technique for the automated directed evolution of proteins. It relies on relating the desired activity of a target protein with the fitness of an infectious bacteriophage which carries the protein's corresponding gene. Proteins with greater desired activity hence confer greater infectivity to their carrier phage. More infectious phage propagate more effectively, selecting for advantageous mutations. Genetic variation is generated using error-prone polymerases on the Cloning vector, phage vectors, and over time the protein accumulates beneficial mutations. This technique is notable for performing hundreds of rounds of selection with minimal human intervention. Principle The central component of PACE is a fixed-volume vessel known as the “lagoon”. The lagoon contains M13 bacteriophage vectors carrying the gene of interest (known as the selection plasmid, or SP), as well as host ''E. coli'' cells that allow the phage to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phage
A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria. The term is derived . Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes (e.g. MS2) and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm. Bacteriophages are among the most common and diverse entities in the biosphere. Bacteriophages are ubiquitous viruses, found wherever bacteria exist. It is estimated there are more than 1031 bacteriophages on the planet, more than every other organism on Earth, including bacteria, combined. Viruses are the most abundant biological entity in the water column of the world's oceans, and the second largest component of biomass after prokaryotes, where up to 9x108 virions per millilitre have been found in microbial mats at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminoacyl-tRNA Synthetases
An aminoacyl-tRNA synthetase (aaRS or ARS), also called tRNA-ligase, is an enzyme that attaches the appropriate amino acid onto its corresponding tRNA. It does so by catalyzing the transesterification of a specific cognate amino acid or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA. In humans, the 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases, one for each amino acid of the genetic code. This is sometimes called "charging" or "loading" the tRNA with an amino acid. Once the tRNA is charged, a ribosome can transfer the amino acid from the tRNA onto a growing peptide, according to the genetic code. Aminoacyl tRNA therefore plays an important role in RNA Translation (biology), translation, the expression of genes to create proteins. Mechanism The synthetase first binds Adenosine triphosphate, ATP and the corresponding amino acid (or its Amino acid synthesis, precursor) to form an aminoacyl-adenylate, relea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenosine
Adenosine (symbol A) is an organic compound that occurs widely in nature in the form of diverse derivatives. The molecule consists of an adenine attached to a ribose via a β-N9- glycosidic bond. Adenosine is one of the four nucleoside building blocks of RNA (and its derivative deoxyadenosine is a building block of DNA), which are essential for all life on Earth. Its derivatives include the energy carriers adenosine mono-, di-, and triphosphate, also known as AMP/ADP/ATP. Cyclic adenosine monophosphate (cAMP) is pervasive in signal transduction. Adenosine is used as an intravenous medication for some cardiac arrhythmias. Adenosyl (abbreviated Ado or 5'-dAdo) is the chemical group formed by removal of the 5′-hydroxy (OH) group. It is found in adenosylcobalamin (an active form of vitamin B12) and as a radical in the radical SAM enzymes. Medical uses Supraventricular tachycardia In individuals with supraventricular tachycardia (SVT), adenosine is a first line trea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soluble Expression PACE
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be "miscible in all proportions" (or just "miscible"). The solute can be a solid, a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations,J. de Swaan Arons and G. A. M. Diepen (1966): "Gas—Gas Equilibria". ''Journal of Chemical Physics'', volum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytidine Deaminase
Cytidine deaminase is an enzyme that in humans is encoded by the ''CDA'' gene. This gene encodes an enzyme involved in pyrimidine salvaging. The encoded protein forms a homotetramer that catalyzes the irreversible hydrolytic deamination of cytidine and deoxycytidine to uridine and deoxyuridine, respectively. It is one of several deaminases responsible for maintaining the cellular pyrimidine pool. Mutations in this gene are associated with decreased sensitivity to the cytosine nucleoside analogue cytosine arabinoside used in the treatment of certain childhood leukemias. Most cytidine deaminases act on RNA, and the few that act on DNA require ssDNA. A related activation-induced (cytidine) deaminase (AID) regulates antibody diversification, especially the process of somatic hypermutation Somatic hypermutation (or SHM) is a cellular mechanism by which the immune system adapts to the new foreign elements that confront it (e.g. microbes). A major component of the process of affinity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
APOBEC1
Apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 also known as C->U-editing enzyme APOBEC-1 is a protein that in humans is encoded by the ''APOBEC1'' gene. This gene encodes a member of the APOBEC, APOBEC protein family and the cytidine deaminase enzyme family. The encoded protein forms a multiple-protein RNA editing holoenzyme with APOBEC1 complementation factor (A1CF). This holoenzyme is involved in the editing of cytosine-to-uracil (C-to-U) nucleotide bases in apolipoprotein B and neurofibromin 1 mRNAs. APOBEC-1 (A1) has been linked with cholesterol control, cancer development and inhibition of viral replication. Its function relies on introducing a stop codon into apolipoprotein B (ApoB) mRNA, which alters lipid metabolism in the gastrointestinal tract. The editing mechanism is highly specific. A1’s deamination of the cytosine base yields uracil, which creates a stop codon in the mRNA. A1 has been linked with both positive and negative health effects. In rode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endotoxin
Lipopolysaccharide (LPS), now more commonly known as endotoxin, is a collective term for components of the outermost membrane of the cell envelope of gram-negative bacteria, such as '' E. coli'' and ''Salmonella'' with a common structural architecture. Lipopolysaccharides are large molecules consisting of three parts: an outer core polysaccharide termed the O-antigen, an inner core oligosaccharide and Lipid A (from which toxicity is largely derived), all covalently linked. In current terminology, the term endotoxin is often used synonymously with LPS, although there are a few endotoxins (in the original sense of toxins that are inside the bacterial cell that are released when the cell disintegrates) that are not related to LPS, such as the so-called delta endotoxin proteins produced by '' Bacillus thuringiensis''. Lipopolysaccharides can have substantial impacts on human health, primarily through interactions with the immune system. LPS is a potent activator of the immune sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacillus Thuringiensis
''Bacillus thuringiensis'' (or Bt) is a gram-positive bacteria, gram-positive, soil-dwelling bacterium, the most commonly used biological pesticide worldwide. ''B. thuringiensis'' also occurs naturally in the gut of caterpillars of various types of moths and butterfly, butterflies, as well as on leaf surfaces, aquatic environments, animal feces, insect-rich environments, flour mills and grain-storage facilities. It has also been observed to parasitize moths such as ''Cadra calidella''—in laboratory experiments working with ''C. calidella'', many of the moths were diseased due to this parasite. During Endospore, sporulation, many Bt strains produce crystal proteins (proteinaceous inclusions), called delta endotoxins, that have Insecticide, insecticidal action. This has led to their use as insecticides, and more recently to genetically modified crops using Bt genes, such as Genetically modified maize#Bt corn, Bt corn. Many crystal-producing Bt strain (biology), strains, though, d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AaRS PACE
Aars or Års, () is a Denmark, Danish town with a population of 8,708 (1 January 2025)BY3: Population 1. January by urban areas, area and population density The Mobile Statbank from Statistics Denmark in Himmerland, Denmark. Administratively, Aars is the municipal seat of Vesthimmerland Municipality and biggest town of Vesthimmerland Municipality, Region Nordjylland since 2007 and it was also the seat of the mayor in the now abolished Aars Municipality. The town was founded in the 14th century. It is one of the four principal towns of Vesthimmerland, the other ones being Farsø, Løgstør and Aalestrup. Aars is a former railway town. It is currently the 77 largest city in Denmark just behind Nivå but in front of Løgten in Aarhus Municipality. It is the 11th biggest town/city in Regio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
