title: Structural ensembles reveal intrinsic disorder for the multi-stimuli responsive bio-mimetic protein Rec1-resilin.
abstract: Rec1-resilin is the first recombinant resilin-mimetic protein polymer, synthesized from exon-1 of the Drosophila melanogaster gene CG15920 that has demonstrated unusual multi-stimuli responsiveness in aqueous solution. Crosslinked hydrogels of Rec1-resilin have also displayed remarkable mechanical properties including near-perfect rubber-like elasticity. The structural basis of these extraordinary properties is not clearly understood. Here we combine a computational and experimental investigation to examine structural ensembles of Rec1-resilin in aqueous solution. The structure of Rec1-resilin in aqueous solutions is investigated experimentally using circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS). Both bench-top and synchrotron SAXS are employed to extract structural data sets of Rec1-resilin and to confirm their validity. Computational approaches have been applied to these experimental data sets in order to extract quantitative information about structural ensembles including radius of gyration, pair-distance distribution function, and the fractal dimension. The present work confirms that Rec1-resilin is an intrinsically disordered protein (IDP) that displays equilibrium structural qualities between those of a structured globular protein and a denatured protein. The ensemble optimization method (EOM) analysis reveals a single conformational population with partial compactness. This work provides new insight into the structural ensembles of Rec1-resilin in solution.
authors.affiliation: Ian Wark Research Institute, University of South Australia, Mawson Lakes campus, Mawson lakes, South Australia 5095, Australia.
authors.forename: Rajkamal
authors.initials: R
authors.lastname: Balu
authors.affiliation: ANSTO, Private Mail Bag, Kirrawee, New South Wales 2232, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Knott
authors.affiliation: Centre for Synchrotron Science, Monash University, Victoria 3800, Australia.
authors.forename: Nathan P
authors.initials: NP
authors.lastname: Cowieson
authors.affiliation: CSIRO Agriculture, Level 6, Queensland Bioscience Precinct, St Lucia, Queensland 4067, Australia.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Elvin
authors.affiliation: CSIRO Manufacturing, Clayton, Victoria 3168, Australia.
authors.forename: Anita J
authors.initials: AJ
authors.lastname: Hill
authors.affiliation: Ian Wark Research Institute, University of South Australia, Mawson Lakes campus, Mawson lakes, South Australia 5095, Australia.
authors.forename: Namita R
authors.initials: NR
authors.lastname: Choudhury
authors.affiliation: Ian Wark Research Institute, University of South Australia, Mawson Lakes campus, Mawson lakes, South Australia 5095, Australia.
authors.forename: Naba K
authors.initials: NK
authors.lastname: Dutta
mesh_terms: D002942:Circular Dichroism; D019476:Insect Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D019476:Insect Proteins; C030951:resilin