Ribose-5-phosphate isomerases: characteristics, structural features, and applications.

Ribose-5-phosphate isomerase (Rpi, EC 5.3.1.6) is widespread in microorganisms, animals, and plants. It has a pivotal role in the pentose phosphate pathway and responsible for catalyzing the isomerization between D-ribulose 5-phosphate and D-ribose 5-phosphate. In recent years, Rpi has received considerable attention as a multipurpose biocatalyst for production of rare sugars, including D-allose, L-rhamnulose, L-lyxose, and L-tagatose. Besides, it has been thought of as a potential drug target in the treatment of trypanosomatid-caused diseases such as Chagas' disease, leishmaniasis, and human African trypanosomiasis. Despite increased research activities, up to now, no systematic review of Rpi has been published. To fill this gap, this paper provides detailed information about the enzymatic properties of various Rpis. Furthermore, structural features, catalytic mechanism, and molecular modifications of Rpis are summarized based on extensive crystal structure research. Additionally, the applications of Rpi in rare sugar production and the role of Rpi in trypanocidal drug design are reviewed. Key points • Fundamental properties of various ribose-5-phosphate isomerases (Rpis). • Differences in crystal structure and catalytic mechanism between RpiA and RpiB. • Application of Rpi as a rare sugar producer and a potential drug target.