PurinePermeasen

PurinePermeasen is a hypothetical membrane-associated protein proposed to mediate the transport of purine nucleobases and related compounds across cellular membranes. The name combines purine with permease, reflecting its proposed role in modulating membrane permeability to purines rather than catalyzing a chemical transformation.

The protein is predicted to be a multipass transmembrane protein that functions as a facilitated diffusion or secondary active transporter. It is thought to form oligomeric assemblies that create a selective pore or binding site for purines such as adenine, guanine, and hypoxanthine. No experimental structure has been reported; supported features include predicted transmembrane helices, conserved polar residues within the pore, and gene neighborhoods with purine salvage and nucleotide metabolism genes.

Distribution and genetics: Candidate PurinePermeasen homologs have been found in diverse bacteria and archaea, with occasional eukaryotic relatives in plastids and mitochondria. In many genomes, purine permease–like genes are found near genes involved in purine salvage and nucleotide metabolism, suggesting a coordinated role in uptake and salvage. Expression appears responsive to purine availability in some transcriptomic studies, consistent with a role in uptake under limiting conditions.

Research status and significance: As a hypothetical protein, PurinePermeasen remains unconfirmed experimentally. If validated, it would advance understanding of purine uptake and salvage and could have applications in metabolic engineering or antimicrobial strategies by targeting purine acquisition pathways.