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Riboswitch-mediated folding sequesters the ribosome-binding site, thereby inhibiting translation. The riboswitch is a ribozyme that cleaves itself in the presence of sufficient concentrations of its metabolite. Riboswitch alternate structures affect the splicing of the pre-mRNA.
The TPP riboswitch, also known as the THI element and Thi-box riboswitch, is a highly conserved RNA secondary structure. It serves as a riboswitch [1][2] that binds thiamine pyrophosphate (TPP) directly and modulates gene expression through a variety of mechanisms in archaea, bacteria and eukaryotes. [3][4][5] TPP is the active form of thiamine ...
A typical operon. In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. [1] The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splicing to create monocistronic mRNAs that are translated separately, i.e. several strands of mRNA that each encode a single gene product.
Attenuator (genetics) In genetics, attenuation is a regulatory mechanism for some bacterial operons that results in premature termination of transcription. The canonical example of attenuation used in many introductory genetics textbooks, [ 1 ] is ribosome-mediated attenuation of the trp operon. Ribosome-mediated attenuation of the trp operon ...
The riboswitch functions by directly sensing a physiological signal. [10] Next, a specific uncharged tRNA binds to a riboswitch element in the transcript, and a structural change occurs in the transcript that promotes expression of the downstream coding sequence. [2] [10] The specifier sequence is the first recognition sequence in the leader. [7]
Histone acetylation and deacetylation. The crystal structure of the nucleosome core particle consisting of H2A , H2B , H3 and H4 core histones, and DNA. The view is from the top through the superhelical axis. Histone acetylation and deacetylation are the processes by which the lysine residues within the N-terminal tail protruding from the ...
Glycine riboswitch. The bacterial glycine riboswitch is an RNA element that can bind the amino acid glycine. Glycine riboswitches usually consist of two metabolite-binding aptamer domains with similar structures in tandem. The aptamers were originally thought to cooperatively bind glycine to regulate the expression of downstream genes.
In the case of nucleic acids, quaternary structure refers to interactions between multiple nucleic acid molecules or between nucleic acids and proteins. Nucleic acid quaternary structure is important for understanding DNA, RNA, and gene expression because quaternary structure can impact function. For example, when DNA is packed into ...