title: Coupled folding and binding of the disordered protein PUMA does not require particular residual structure.
abstract: Many cellular proteins are 'disordered' in isolation. A subset of these intrinsically disordered proteins (IDPs) can, upon binding another molecule, fold to a well-defined three-dimensional structure. In the structurally heterogeneous, unbound ensemble of these IDPs, conformations are likely to exist that, in part, resemble the final bound form. It has been suggested that these conformations, displaying 'residual structure', could be important for the mechanism of such coupled folding and binding reactions. PUMA, of the BCL-2 family, is an IDP in isolation but will form a single, contiguous α-helix upon binding the folded protein MCL-1. Using the helix-breaking residue proline, we systematically target each potential turn of helix of unbound PUMA and assess the binding to MCL-1 using time-resolved stopped-flow techniques. All proline-containing mutants bound, and although binding was weaker than the wild-type protein, association rate constants were largely unaffected. We conclude that population of particular residual structure, containing a specific helical turn, is neither required for the binding nor for fast association of PUMA and MCL-1.
authors.affiliation: Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Rogers
authors.forename: Chi T
authors.initials: CT
authors.lastname: Wong
authors.forename: Jane
authors.initials: J
authors.lastname: Clarke
mesh_terms: D051017:Apoptosis Regulatory Proteins / Q000737:chemistry*; D001665:Binding Sites; D006801:Humans; D008958:Models, Molecular; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D011518:Proto-Oncogene Proteins / Q000737:chemistry*
chemical_list: D051017:Apoptosis Regulatory Proteins; C438378:BBC3 protein, human; C579095:MCL1 protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D011518:Proto-Oncogene Proteins