Nucleic acid structure refers to the structure of nucleic acids such as DNA and RNA It is often divided into four different levels:
- Primary structure—the raw sequence of nucleobases of each of the component DNA strands;
- Secondary structure—the set of interactions between bases, i.e., which parts of which strands are bound to each other;
- Tertiary structure—the locations of the atoms in three-dimensional space, taking into consideration geometrical and steric constraints; and
- Quaternary structure—the higher-level organization of DNA in chromatin, or to the interactions between separate RNA units in the ribosome or spliceosome.
