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Jeebus
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Does anyone know by chance what a T-helix is?
Biochim Biophys Acta. 1999 Dec 10;1489(1):181-206.
Triple helix formation and the antigene strategy for sequence-specific control of gene expression.
Praseuth D, Guieysse AL, Helene C.
Laboratoire de Biophysique, INSERM U201, CNRS UMR 8646, Museum National d'Histoire Naturelle, Paris, France.
Specific gene expression involves the binding of natural ligands to the DNA base pairs. Among the compounds rationally designed for artificial regulation of gene expression, oligonucleotides can bind with a high specificity of recognition to the major groove of double helical DNA by forming Hoogsteen type bonds with purine bases of the Watson-Crick base pairs, resulting in triple helix formation. Although the potential target sequences were originally restricted to polypurine-polypyrimidine sequences, considerable efforts were devoted to the extension of the repertoire by rational conception of appropriate derivatives. Efficient tools based on triple helices were developed for various biochemical applications such as the development of highly specific artificial nucleases. The antigene strategy remains one of the most fascinating fields of triplex application to selectively control gene expression. Targeting of genomic sequences is now proved to be a valuable concept on a still limited number of studies; local mutagenesis is in this respect an interesting application of triplex-forming oligonucleotides on cell cultures. Oligonucleotide penetration and compartmentalization in cells, stability to intracellular nucleases, accessibility of the target sequences in the chromatin context, the residence time on the specific target are all limiting steps that require further optimization. The existence and the role of three-stranded DNA in vivo, its interaction with intracellular proteins is worth investigating, especially relative to the regulation of gene transcription, recombination and repair processes.
A T-Helix is a type of secondary structure found in protein molecules. It is characterized by two alpha helices connected by a short segment, forming a T-shape.
A T-Helix is formed through hydrogen bonding between the amino acid residues in the two alpha helices. This bonding stabilizes the structure and allows it to maintain its shape.
The function of a T-Helix is not well understood, but it is believed to play a role in protein-protein interactions and in the stability of larger protein structures.
A T-Helix differs from other secondary structures, such as alpha helices and beta sheets, in its shape and the type of bonding that holds it together. It is also less common and found in a smaller percentage of protein structures.
Currently, there is no reliable method for predicting the presence of a T-Helix in a protein sequence. However, with advancements in technology and research, this may be possible in the future.