Crystallization and X-ray crystallographic analysis of ribose 5-phosphate isomerase B in complex with its ligand from Vibrio vulnificus

Ribose 5-phosphate isomerase is an enzyme that interconverts ribose 5-phosphate and ribulose 5-phosphate in the pentose phosphate pathway, which participates in NADPH generation, as well as an oxidative and non-oxidative synthesis of pentose sugars. Two distinct forms, ribose 5-phosphate isomerase A (RpiA) and ribose 5-phosphate isomerase B (RpiB), show no sequence identity even though they exist as ubiquitous, highly-conserved proteins in most kingdoms. RpiB from pathogenic, marine Vibrio vulnificus YJ016 (VvRpiB) was purified, crystallized, and analyzed to determine its structure in the apo form and in complex with a ligand. Crystals of the apo form of VvRpiB diffracted X-rays to 3.06 Å resolution, belonging to tetragonal space group I41 while co-crystals of VvRpiB with R5P belonged to the monoclinic space group C2 and diffracted X-rays to 2.07 Å resolution.