title: Deriving the ultrastructure of α-crustacyanin using lower-resolution structural and biophysical methods.
abstract: The low-resolution structure of α-crustacyanin has been determined to 30 Å resolution using negative-stain electron microscopy (EM) with single-particle averaging. The protein, which is an assembly of eight β-crustacyanin dimers, appears asymmetrical and rather open in layout. A model was built to the EM map using the X-ray crystallographic structure of β-crustacyanin guided by PISA interface analyses. The model has a theoretical sedimentation coefficient that matches well with the experimentally derived value from sedimentation velocity analytical ultracentrifugation. Additionally, the EM model has similarities to models calculated independently by rigid-body modelling to small-angle X-ray scattering (SAXS) data and extracted in silico from the β-crustacyanin crystal lattice. Theoretical X-ray scattering from each of these models is in reasonable agreement with the experimental SAXS data and together suggest an overall design for the α-crustacyanin assembly.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester M13 9PL, UK.
authors.forename: Natasha H
authors.initials: NH
authors.lastname: Rhys
authors.forename: Ming Chuan
authors.initials: MC
authors.lastname: Wang
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Jowitt
authors.forename: John R
authors.initials: JR
authors.lastname: Helliwell
authors.forename: J Günter
authors.initials: JG
authors.lastname: Grossmann
authors.forename: Clair
authors.initials: C
authors.lastname: Baldock
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000648:ultrastructure*; D018360:Crystallography, X-Ray / Q000379:methods; D008854:Microscopy, Electron; D053838:Scattering, Small Angle; D014461:Ultracentrifugation
chemical_list: D002352:Carrier Proteins; C018494:crustacyanins