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Thus, acetylation of histones is known to increase the expression of genes through transcription activation. Deacetylation performed by HDAC molecules has the opposite effect. By deacetylating the histone tails, the DNA becomes more tightly wrapped around the histone cores, making it harder for transcription factors to bind to the DNA.
DNA polymerase III synthesizes base pairs at a rate of around 1000 nucleotides per second. [3] DNA Pol III activity begins after strand separation at the origin of replication. Because DNA synthesis cannot start de novo, an RNA primer, complementary to part of the single-stranded DNA, is synthesized by primase (an RNA polymerase): [citation ...
Stem-loops are nucleic acid secondary structural elements which form via intramolecular base pairing in single-stranded DNA or RNA. They are also referred to as hairpins or hairpin loops. A stem-loop occurs when two regions of the same nucleic acid strand, usually complementary in nucleotide sequence, base-pair to form a double helix that ends ...
A hydrohalogenation reaction is the electrophilic addition of hydrogen halides like hydrogen chloride or hydrogen bromide to alkenes to yield the corresponding haloalkanes. [ 1 ] [ 2 ] [ 3 ] If the two carbon atoms at the double bond are linked to a different number of hydrogen atoms, the halogen is found preferentially at the carbon with fewer ...
Nucleic acid metabolism is a collective term that refers to the variety of chemical reactions by which nucleic acids (DNA and/or RNA) are either synthesized or degraded. Nucleic acids are polymers (so-called "biopolymers") made up of a variety of monomers called nucleotides .
ADPr is an important mechanism in gene regulation that affects chromatin organization, the binding of transcription factors, and mRNA processing through poly-ADP ribose polymerase (PARP) enzymes. There are multiple types of PARP proteins, but the subclass of DNA-dependent PARP proteins including PARP-1, PARP-2, and PARP-3 interact with the ...
The mechanism occurs in the framework of a synaptic complex (1) including both DNA sites in parallel orientation. While branch-migration explains the specific homology requirements and the reversibility of the process in a straightforward manner, it cannot be reconciled with the motions recombinase subunits have to undergo in three dimensions.
Halogenation of saturated hydrocarbons is a substitution reaction. The reaction typically involves free radical pathways. The regiochemistry of the halogenation of alkanes is largely determined by the relative weakness of the C–H bonds. This trend is reflected by the faster reaction at tertiary and secondary positions.