Visualizing the transiently populated closed-state of human HSP90 ATP binding domain.

HSP90 are abundant molecular chaperones, assisting the folding of several hundred client proteins, including substrates involved in tumor growth or neurodegenerative diseases. A complex set of large ATP-driven structural changes occurs during HSP90 functional cycle. However, the existence of such structural rearrangements in apo HSP90 has remained unclear.

Structural basis for the inhibition of IAPP fibril formation by the co-chaperonin prefoldin.

Chaperones, as modulators of protein conformational states, are key cellular actors to prevent the accumulation of fibrillar aggregates. Here, we integrated kinetic investigations with structural studies to elucidate how the ubiquitous co-chaperonin prefoldin inhibits diabetes associated islet amyloid polypeptide (IAPP) fibril formation. We demonstrated that both human and archaeal prefoldin interfere similarly with the IAPP fibril elongation and secondary nucleation pathways.

The Plastid-Encoded RNA Polymerase-Associated Protein PAP9 Is a Superoxide Dismutase With Unusual Structural Features.

In Angiosperms, the plastid-encoded RNA polymerase (PEP) is a multimeric enzyme, essential for the proper expression of the plastid genome during chloroplast biogenesis. It is especially required for the light initiated expression of photosynthesis genes and the subsequent build-up of the photosynthetic apparatus. The PEP complex is composed of a prokaryotic-type core of four plastid-encoded subunits and 12 nuclear-encoded PEP-associated proteins (PAPs).

Optimized precursor to simplify assignment transfer between backbone resonances and stereospecifically labelled valine and leucine methyl groups: application to human Hsp90 N-terminal domain.

Methyl moieties are highly valuable probes for quantitative NMR studies of large proteins. Hence, their assignment is of the utmost interest to obtain information on both interactions and dynamics of proteins in solution. Here, we present the synthesis of a new precursor that allows connection of leucine and valine pro-S methyl moieties to backbone atoms by linear C-chains.

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.