Researchers discover the precise make-up of a molecular chaperone complex
A complex made up of three proteins, Hsp90, Sgt1, and Rar1, is thought to stabilise an important immune protein known as nucleotide-binding domain and leucine-rich repeat containing protein. While the structure of the Sgt1-Hsp90-Rar1 protein is known, the stoichiometry of the complex has remained elusive. In a paper published in Frontiers in Molecular Biosciences, Dr Chrisostomos Prodromou of the University of Sussex and Dr Minghao Zhang of the University of Oxford worked with Professor Giuliano Siligardi at the Circular Dichroism beamline (B23) at Diamond Light Source to clarify the detailed make-up of the complex. Using synchrotron radiation circular dichroism, they revealed that it consists of an Hsp90 dimer, two Sgt1 molecules, and a single Rar1 molecule. The stoichiometry of the full complex potentially allows two NLR molecules to bind, a finding which may open avenues of research into how these proteins form dimers.
Figure: (extract) The structure of the Sgt1-Hsp90-Rar1 complex with an Hsp90 dimer, two Sgt1 molecules, and a single Rar1. Entire image here.