The psaA RNA motif describes a class of RNAs with a common secondary structure.

The psaAB genes encode proteins that form subunits in the photosystem I structure used for photosynthesis.

[3] A region of the psaA RNA motif corresponds to the expected sequence of a binding site of the NtcA protein, which is involved in nitrogen regulation.

[4] Structurally, the psaA RNA motif consists of a somewhat complex arrangement of stems resulting from base pairing, and many stem-loops are terminated by the stable UNCG tetraloop.

Most of the conserved nucleotides in the motif participate in standard Watson-Crick base pairs.