The three-dimensional Structure of "Lonely Guy" from Claviceps purpurea provides insights into the phosphoribohydrolase function of Rossmann fold-containing lysine decarboxylase-like proteins

The recently discovered cytokinin-specific phosphoribohydrolase 'Lonely Guy' (LOG) is a key enzyme of cytokinin biosynthesis, converting inactive cytokinin nucleotides into biologically active free-bases. We have determined the crystal structures of LOG from C. purpurea (cpLOG) and its complex with the enzymatic product phosphoribose. The structures reveal a dimeric arrangement of Rossmann folds, with the ligands bound to large pockets at the interface between cpLOG monomers. Structural comparisons highlight the homology of cpLOG to putative lysine decarboxylases. Extended sequence analysis enabled identification of a distinguishing LOG sequence signature. Taken together, our data suggest phosphoribohydrolase activity for several proteins of unknown function. This article is protected by copyright. All rights reserved.