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Helix-turn-helix Motif
Helix-turn-helix is a DNA-binding domain (DBD). The helix-turn-helix (HTH) is a major structural motif capable of binding DNA. Each monomer incorporates two alpha helix, α helices, joined by a short strand of amino acids, that bind to the major groove of DNA. The HTH motif occurs in many proteins that regulate gene expression. It should not be confused with the helix–loop–helix motif. Discovery The discovery of the helix-turn-helix motif was based on similarities between several genes encoding Transcription (genetics), transcription regulatory proteins from bacteriophage lambda and ''Escherichia coli'': Cro, Catabolite activator protein, CAP, and cI protein, λ repressor, which were found to share a common 20–25 amino acid sequence that facilitates DNA recognition. Function The helix-turn-helix motif is a DNA-binding motif. The recognition and binding to DNA by helix-turn-helix proteins is done by the two α helices, one occupying the N-terminus, N-terminal end of the mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambda Repressor 1LMB
Lambda (; uppercase , lowercase ; , ''lám(b)da'') is the eleventh letter of the Greek alphabet, representing the Dental, alveolar and postalveolar lateral approximants, voiced alveolar lateral approximant . In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoenician alphabet, Phoenician Lamed. Lambda gave rise to the Latin script, Latin L and the Cyrillic script, Cyrillic El (Cyrillic), El (Л). The ancient Alexandrine grammarians, grammarians and dramatists give evidence to the pronunciation as () in Classical Greek times. In Modern Greek, the name of the letter, Λάμδα, is pronounced . In Epichoric alphabets, early Greek alphabets, the shape and orientation of lambda varied. Most variants consisted of two straight strokes, one longer than the other, connected at their ends. The angle might be in the upper-left, lower-left ("Western" alphabets) or top ("Eastern" alphabets). Other variants had a vertical line with a horizontal or sloped ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYB (gene)
Myb genes are part of a large gene family of transcription factors found in animals and plants. In humans, it includes Myb proto-oncogene like 1 and Myb-related protein B in addition to MYB proper. Members of the extended SANT/Myb family also include the SANT domain and other similar all-helical homeobox-like domains. Function Viral The Myb gene family is named after the eponymous gene in Alpharetrovirus, Avian myeloblastosis virus. The viral Myb (v-Myb, ) recognizes the sequence 5'-YAACKG-3'. It causes myeloblastosis (myeloid leukemia) in chickens. Compared to the normal animal cellular Myb (c-myb), v-myb contains deletions in the C-terminal regulatory domain, leading to aberrant activation of other oncogenes. Animals Myb proto-oncogene protein is a member of the MYB (myeloblastosis) family of transcription factors. The protein contains three domains, an N-terminus, N-terminal DNA-binding domain, a central transcriptional activation domain and a C-terminal domain involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EMBL
The European Molecular Biology Laboratory (EMBL) is an intergovernmental organization dedicated to molecular biology research and is supported by 29 member states, two prospect member states, and one associate member state. EMBL was created in 1974 and is funded by public research money from its member states. Research at EMBL is conducted by more than 110 independent research groups and service teams covering the spectrum of molecular biology. The Laboratory operates from six sites: the main laboratory in Heidelberg (Germany), and sites in Barcelona (Spain), Grenoble (France), Hamburg (Germany), Hinxton (the European Bioinformatics Institute (EBI), in England), and Rome (Italy). EMBL groups and laboratories perform basic research in molecular biology and molecular medicine as well as train scientists, students, and visitors. The organization aids in the development of services, new instruments and methods, and technology in its member states. Israel is the only full member stat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Finger
A zinc finger is a small protein structural motif that is characterized by the coordination of one or more zinc ions (Zn2+) which stabilizes the fold. The term ''zinc finger'' was originally coined to describe the finger-like appearance of a hypothesized structure from the African clawed frog (''Xenopus laevis'') transcription factor IIIA. However, it has been found to encompass a wide variety of differing protein structures in eukaryotic cells. '' Xenopus laevis'' TFIIIA was originally demonstrated to contain zinc and require the metal for function in 1983, the first such reported zinc requirement for a gene regulatory protein followed soon thereafter by the Krüppel factor in ''Drosophila''. It often appears as a metal-binding domain in multi-domain proteins. Proteins that contain zinc fingers (zinc finger proteins) are classified into several different structural families. Unlike many other clearly defined supersecondary structures such as Greek keys or β hairpins, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Structure
Protein secondary structure is the local spatial conformation of the polypeptide backbone excluding the side chains. The two most common Protein structure#Secondary structure, secondary structural elements are alpha helix, alpha helices and beta sheets, though beta turns and omega loops occur as well. Secondary structure elements typically spontaneously form as an intermediate before the protein protein folding, folds into its three dimensional protein tertiary structure, tertiary structure. Secondary structure is formally defined by the pattern of hydrogen bonds between the Amine, amino hydrogen and carboxyl oxygen atoms in the peptide backbone chain, backbone. Secondary structure may alternatively be defined based on the regular pattern of backbone Dihedral angle#Dihedral angles of proteins, dihedral angles in a particular region of the Ramachandran plot regardless of whether it has the correct hydrogen bonds. The concept of secondary structure was first introduced by Kaj Ulrik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA-binding Protein
DNA-binding proteins are proteins that have DNA-binding domains and thus have a specific or general affinity for single- or double-stranded DNA. Sequence-specific DNA-binding proteins generally interact with the major groove of B-DNA, because it exposes more functional groups that identify a base pair. Examples DNA-binding proteins include transcription factors which modulate the process of transcription, various polymerases, nucleases which cleave DNA molecules, and histones which are involved in chromosome packaging and transcription in the cell nucleus. DNA-binding proteins can incorporate such domains as the zinc finger, the helix-turn-helix, and the leucine zipper (among many others) that facilitate binding to nucleic acid. There are also more unusual examples such as transcription activator like effectors. Non-specific DNA-protein interactions Structural proteins that bind DNA are well-understood examples of non-specific DNA-protein interactions. Within chromosomes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiple Antibiotic Resistance
Multiple drug resistance (MDR), multidrug resistance or multiresistance is antimicrobial resistance shown by a species of microorganism to at least one antimicrobial drug in three or more antimicrobial categories. Antimicrobial categories are classifications of antimicrobial agents based on their mode of action and specific to target organisms. The MDR types most threatening to public health are MDR bacteria that resist multiple antibiotics; other types include MDR viruses, parasites (resistant to multiple antifungal, antiviral, and antiparasitic drugs of a wide chemical variety). Recognizing different degrees of MDR in bacteria, the terms ''extensively drug-resistant'' (''XDR'') and ''pandrug-resistant'' (''PDR'') have been introduced. ''Extensively drug-resistant (XDR)'' is the non-susceptibility of one bacteria species to all antimicrobial agents except in two or less antimicrobial categories. Within XDR, ''pandrug-resistant (PDR)'' is the non-susceptibility of bacteria to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ETS Transcription Factor Family
In the field of molecular biology, the ETS (E26 transformation-specific or Erythroblast Transformation Specific) family is one of the largest families of transcription factors and is unique to animals. There are 28 genes in humans, 27 in the mouse, 10 in '' Caenorhabditis elegans'' and 9 in '' Drosophila.'' The founding member of this family was identified as a gene transduced by the leukemia virus, E26. The members of the family have been implicated in the development of different tissues as well as cancer progression. Subfamilies The ETS (Erythroblast Transformation Specific)family is divided into 12 subfamilies, which are listed below: Structure All ETS (Erythroblast Transformation Specific) family members are identified through a highly conserved DNA binding domain, the ETS domain, which is a winged helix-turn-helix structure that binds to DNA sites with a central GGA(A/T) DNA sequence. As well as DNA-binding functions, evidence suggests that the ETS domain is also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Sheet
The beta sheet (β-sheet, also β-pleated sheet) is a common motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet. A β-strand is a stretch of polypeptide chain typically 3 to 10 amino acids long with backbone in an extended conformation. The supramolecular association of β-sheets has been implicated in the formation of the fibrils and protein aggregates observed in amyloidosis, Alzheimer's disease and other proteinopathies. History The first β-sheet structure was proposed by William Astbury in the 1930s. He proposed the idea of hydrogen bonding between the peptide bonds of parallel or antiparallel extended β-strands. However, Astbury did not have the necessary data on the bond geometry of the amino acids in order to build accurate models, especially since he did not then know that the peptide bond was planar. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-sheet
The beta sheet (β-sheet, also β-pleated sheet) is a common structural motif, motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone chain, backbone hydrogen bonds, forming a generally twisted, pleated sheet. A β-strand is a stretch of peptide, polypeptide chain typically 3 to 10 amino acids long with backbone in an extended conformational isomerism, conformation. The supramolecular association of β-sheets has been implicated in the formation of the Amyloid fibril, fibrils and Amyloid plaques, protein aggregates observed in amyloidosis, Alzheimer's disease and other Proteinopathy, proteinopathies. History The first β-sheet structure was proposed by William Astbury in the 1930s. He proposed the idea of hydrogen bonding between the peptide bonds of parallel or antiparallel extended β-strands. However, Astbury did not have the necessary data on the bond geometry of the amino acids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TetR
Tet Repressor proteins (otherwise known as TetR) are proteins playing an important role in conferring antimicrobial resistance, antibiotic resistance to large categories of bacterial species. Tetracycline (Tc) is a broad family of antibiotics to which bacteria have evolved resistance. Tc normally kills bacteria by binding to the bacterial ribosome and halting protein synthesis. The expression of Tc resistance genes is regulated by the repressor TetR. TetR represses the expression of TetA, a membrane protein that pumps out substances toxic to the bacteria like Tc, by binding the ''tetA'' Operator (biology), operator. In Tc-resistant bacteria, TetA will pump out Tc before it can bind to the ribosome because the repressive action of TetR on TetA is halted by binding of Tc to TetR. Therefore, TetR may have an important role in helping scientists to better understand mechanisms of Antibiotic resistant, antibiotic resistance and how to treat antibiotic resistant bacteria. TetR is one of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
