polyuridylic

Polyuridylic acid, commonly referred to as poly(U), is a synthetic homopolymer composed of repeating uridylic acid (UMP) nucleotides. It is a key reagent in molecular biology and biochemistry, particularly in studies involving RNA and protein synthesis. Poly(U) consists of a linear chain of uracil bases linked by phosphodiester bonds to a ribose sugar backbone, resembling natural messenger RNA (mRNA) but lacking the diversity of nucleotide sequences found in biological systems.

Poly(U) is widely used as a template in in vitro translation systems to synthesize proteins. When combined with ribosomes and transfer RNA (tRNA) carrying amino acids, poly(U) directs the production of polyphenylalanine, a polypeptide composed exclusively of phenylalanine residues. This system was instrumental in early research on the genetic code, helping to elucidate the relationship between nucleotide triplets and specific amino acids.

The molecule is also employed in studies of RNA-protein interactions, as its uniform sequence allows for controlled experiments on binding affinities and specificity. Poly(U) can form secondary structures, such as hairpin loops, which influence its interaction with proteins like poly(U)-binding proteins (PUFs) involved in RNA stability and localization. Additionally, it serves as a model substrate for investigating RNA degradation mechanisms, including those mediated by ribonucleases.

Poly(U) is typically synthesized chemically or enzymatically and is available commercially for laboratory use. Its stability and predictable behavior make it a valuable tool in both fundamental research and applied biotechnology, particularly in the development of synthetic biology approaches. While not naturally occurring in significant quantities, its synthetic accessibility ensures its continued relevance in molecular studies.