title: Complementing structural information of modular proteins with small angle neutron scattering and contrast variation.
abstract: Many macromolecules in the cell function by forming multi-component assemblies. We have applied the technique of small angle neutron scattering to study a nucleic acid-protein complex and a multi-protein complex. The results illustrate the versatility and applicability of the method to study macromolecular assemblies. The neutron scattering experiments, complementing X-ray solution scattering data, reveal that the conserved catalytic domain of RNase E, an essential ribonuclease in Escherichia coli (E. coli), undergoes a marked conformational change upon binding a 5'monophosphate-RNA substrate analogue. This provides the first evidence in support of an allosteric mechanism that brings about RNA substrate cleavage. Neutron contrast variation of the multi-protein TIM10 complex, a mitochondrial chaperone assembly comprising the subunits Tim9 and Tim10, has been used to determine a low-resolution shape reconstruction of the complex, highlighting the integral subunit organization. It shows characteristic features involving protrusions that could be assigned to the six subunits forming the complex.
authors.affiliation: Molecular Biophysics Group, STFC Daresbury Laboratory, Daresbury Science and Innovation Campus, Warrington, Cheshire WA4 AD, UK. j.g.grossmann@dl.ac.uk
authors.forename: J G
authors.initials: JG
authors.lastname: Grossmann
authors.forename: A J
authors.initials: AJ
authors.lastname: Callaghan
authors.forename: M J
authors.initials: MJ
authors.lastname: Marcaida
authors.forename: B F
authors.initials: BF
authors.lastname: Luisi
authors.forename: F H
authors.initials: FH
authors.lastname: Alcock
authors.forename: K
authors.initials: K
authors.lastname: Tokatlidis
authors.forename: M
authors.initials: M
authors.lastname: Moulin
authors.forename: M
authors.initials: M
authors.lastname: Haertlein
authors.forename: P
authors.initials: P
authors.lastname: Timmins
mesh_terms: D020134:Catalytic Domain; D004722:Endoribonucleases / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008958:Models, Molecular; D033363:Neutron Diffraction; D009696:Nucleic Acids / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D008565:Membrane Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D009696:Nucleic Acids; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; C107250:TIM10 protein, S cerevisiae; D012313:RNA; D004722:Endoribonucleases; C022537:ribonuclease E