The speF RNA motif is a putative regulatory element found in Alphaproteobacteria upstream of speF genes that encode an ornithine decarboxylase from the polyamide synthesis pathway [16086852]. In-line probing of this likely riboswitch motif supports its predicted secondary structure. Testing of metabolites from the polyamide biosynthetic pathway (L-ornithine, L-lysine, meso-diaminopimelate, putrescine, cadaverine, or spermidine) did not reveal a molecular effector of the speF regulatory RNA [16086852].