Backbone NMR Assignments and Secondary Structure Determination of a Cupin-family Protein YaiE from Escherichia coli

Cupin-superfamily proteins represent the most functionally diverse groups of proteins and include a huge number of functionally uncharacterized proteins. Recently, YaiE, a cupin protein from Escherichia coli has been suggested to be involved in a novel activity of pyrimidine/purine nucleoside phosphorylase (PPNP). In the present study, we achieved a complete backbone NMR assignments of YaiE, by a series of heteronuclear multidimensional NMR experiments on its [ 13 C/ 15 N]-enriched sample. Subsequently, secondary structure analysis using the assigned chemical shift values identified 10 obvious β-strands and a tentative 3 10 -helix. Taken all together, the results constitute the first structural characterization of a putative PPNP cupin protein.