title: Synergistic use of synchrotron radiation techniques for biological samples in solution: a case study on protein-ligand recognition by the peroxisomal import receptor Pex5p.
abstract: Circular dichroism spectropolarimetry and X-ray scattering data, obtained using synchrotron radiation, can yield information about the secondary and tertiary structure of proteins in solution. These techniques have been used to analyse the architecture and shape of a complex of two proteins in solution. The crystal structures of two separate proteins, the C-terminal domain of Pex5p and SCP2, are available but their complex has not previously been structurally characterized. Circular dichroism spectropolarimetry indicated that complex formation requires little secondary structure rearrangement. X-ray scattering data fit an elongated irregular 'shoe'-shaped particle of the complex of the two proteins, with dimensions of the order of 30 A x 40 A x 90 A. Comparison with the known crystal structures suggests that this 'shoe' shape requires a conformational change of the C-terminus of SCP2 to appropriately locate its peroxisomal targeting signal type-1 recognition motif into the binding pocket of the Pex5p receptor. Implications of the combined use of synchrotron-based circular dichroism spectropolarimetry and X-ray scattering in structural biology and proteomics are discussed.
authors.affiliation: EMBL-Hamburg, c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany.
authors.forename: W A
authors.initials: WA
authors.lastname: Stanley
authors.forename: A
authors.initials: A
authors.lastname: Sokolova
authors.forename: A
authors.initials: A
authors.lastname: Brown
authors.forename: D T
authors.initials: DT
authors.lastname: Clarke
authors.forename: M
authors.initials: M
authors.lastname: Wilmanns
authors.forename: D I
authors.initials: DI
authors.lastname: Svergun
mesh_terms: D001665:Binding Sites; D002352:Carrier Proteins / Q000032:analysis / Q000737:chemistry*; D002942:Circular Dichroism / Q000379:methods*; D003198:Computer Simulation; D008024:Ligands; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000032:analysis / Q000737:chemistry; D000074435:Peroxisome-Targeting Signal 1 Receptor; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000032:analysis / Q000737:chemistry*; D012996:Solutions; D017356:Synchrotrons; D018511:Systems Integration; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D002352:Carrier Proteins; D008024:Ligands; D046912:Multiprotein Complexes; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D012996:Solutions; C072087:sterol carrier proteins