Bovine L40 has been identified as a secondary RNA binding protein [1]. L40 is fused to a ubiquitin protein [2].

1: RNA binding proteins of the large subunit of bovine mitochondrial ribosomes. Piatyszek MA, Denslow ND, O'Brien TW; Nucleic Acids Res 1988;16:2565-2583. PMID:3129699

2: The carboxyl extensions of two rat ubiquitin fusion proteins are ribosomal proteins S27a and L40. Chan YL, Suzuki K, Wool IG; Biochem Biophys Res Commun 1995;215:682-690. PMID:7488009