Nucleic acid quaternary structure

For example, when DNA is packed into heterochromatin, therefore exhibiting a type of quaternary structure, gene transcription will be inhibited.

The term has also been used to describe the hierarchical assembly of artificial nucleic acid building blocks used in DNA nanotechnology.

Because the human genome is so large, DNA must be condensed into chromatin, which consists of repeating units known as nucleosomes.

Furthermore, post-translational modifications can be made to the core histone tail domains, which lead to changes in DNA quaternary structure and therefore gene expression.

For instance, an enzyme writer can methylate Lysine-9 of the H3 core protein, which is found in the H3 histone tail domain.

Symmetrical complexes of RNA molecules are extremely uncommon compared to protein oligomers.

[1] One example of an RNA homodimer is the VS ribozyme from Neurospora, with its two active sites consisting of nucleotides from both monomers.

[9] The best known example of RNA forming quaternary structures with proteins is the ribosome, which consists of multiple rRNAs, supported by rProteins.

Riboswitches are a type of mRNA structure that help regulate gene expression and often bind a diverse set of ligands.

Riboswitches determine how gene expression responds to varying concentrations of small molecules in the cell[12] This motif has been observed in flavin mononucleotide (FMN), cyclic di-AMP (c-di-AMP), and glycine.

[1] Depending on where a riboswitch binds and how it is arranged, it can suppress or allow a gene to be expressed[12] Symmetry is an important part of biomolecular three-dimensional configurations.

In order for a polypeptide to be formed, proper association of the mRNA and both of the ribosome subunits must occur.

These lone adenosines extend from outward and allow RNA molecules to bind other nucleic acids in the minor groove.

[1] Of note, it has been observed through high resolution imaging that tRNA interacts with the quaternary structure of bacterial 70S ribosome and other proteins.

[1] pRNA is able to form into a quaternary structure by oligimerizing to create the capsid that encloses the genomic DNA of bacteriophage.

Several molecules of pRNA surround the genome, and through stacking interactions and base pairing the pRNAs enclose and the protect the DNA.

Nucleic acid primary structure Nucleic acid secondary structure Nucleic acid tertiary structure Nucleic acid quaternary structure
The image above contains clickable links
The image above contains clickable links
Interactive image of nucleic acid structure (primary, secondary, tertiary, and quaternary) using DNA helices and examples from the VS ribozyme and telomerase and nucleosome . ( PDB : ADNA , 1BNA , 4OCB , 4R4V , 1YMO , 1EQZ ​)
The image above contains clickable links
The image above contains clickable links
DNA coils and winds around histone proteins to condense into chromatin.
The three-dimensional folding motif known as the kissing loop. In this diagram, two kissing loop models are overlaid to show structural similarities. The white backbone and pink bases are from B. subtilis , and the gray backbone and blue bases are from V. vulnificus . [ 8 ]
A Minor Motif interaction