The order of neighbouring amino acids in a protein or of the purine or pyrimidine bases in RNA or DNA.
See also: primary structure
Source:
PAC, 1997, 69, 1251. 'Glossary of terms used in bioinorganic chemistry (IUPAC Recommendations 1997)' on page 1296 (https://doi.org/10.1351/pac199769061251)