Backbone and methyl resonances assignment of the 87 kDa prefoldin from Pyrococcus horikoshii.

Prefoldin is a heterohexameric protein assembly which acts as a co-chaperonin for the well conserved Hsp60 chaperonin, present in archaebacteria and the eukaryotic cell cytosol. Prefoldin is a holdase, capturing client proteins and subsequently transferring them to the Hsp60 chamber for refolding. The chaperonin family is implicated in the early stages of protein folding and plays an important role in proteostasis in the cytosol. Here, we report the assignment of H, N, C', C, C, H, and C chemical shifts of the 87 kDa prefoldin from the hyperthermophilic archaeon Pyrococcus horikoshii, consisting of two α and four β subunits. 100% of the [C, H]-resonances of A, I, I, T, V methyl groups were successfully assigned for both subunits. For the β subunit, showing partial peak doubling, 80% of the backbone resonances were assigned. In the α subunit, large stretches of backbone resonances were not detectable due to slow (μs-ms) time scale dynamics. This conformational exchange limited the backbone sequential assignment of the α subunit to 57% of residues, which corresponds to 84% of visible NMR signals.