This small acidic protein is found in 30S ribosomal subunit of cyanobacteria and plant plastids. In plants it has been named plastid-specific ribosomal protein 3 (PSRP-3), and in cyanobacteria it is named Ycf65. Plastid-specific ribosomal proteins may mediate the effects of nuclear factors on plastid translation. The acidic PSRPs are thought to contribute to protein-protein interactions in the 30S subunit, and are not thought to bind RNA [1].

1: The plastid ribosomal proteins. Identification of all the proteins in the 30 S subunit of an organelle ribosome (chloroplast). Yamaguchi K, von Knoblauch K, Subramanian AR; J Biol Chem 2000;275:28455-28465. PMID:10874039