title: Hydrodynamic data show that C1- inhibitor of complement forms compact complexes with C1-r and C1-s.
abstract: The C1- inhibitor of the complement cascade forms stoichiometric complexes with C1-r and C1-s and controls the activation of first component C1 of complement. Literature sedimentation coefficients s degrees 20,w for the complexes formed between C1- inhibitor, C1-r and C1-s were analysed using frictional ratios and the hydrodynamic sphere approach. A head-and-tail two-domain model for C1- inhibitor was combined with cylindrical hydrodynamic models for the six-domain structures of C1-r and C1-s. The hydrodynamic data show that the heavily glycosylated N-terminal domain of C1- inhibitor is positioned close to the two complement 'short consensus repeat' domains found in the centre of C1-r and C1-s.
authors.affiliation: Department of Biochemistry and Chemistry, Royal Free Hospital School of Medicine, London, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Perkins
mesh_terms: D003167:Complement Activation; D003172:Complement C1 / Q000737:chemistry* / Q000378:metabolism; D003174:Complement C1 Inactivator Proteins / Q000737:chemistry* / Q000378:metabolism; D016384:Consensus Sequence; D008958:Models, Molecular; D011487:Protein Conformation; D012697:Serine Endopeptidases / Q000737:chemistry / Q000378:metabolism; D015843:Serpins / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship; D014867:Water / Q000378:metabolism*
chemical_list: D003172:Complement C1; D003174:Complement C1 Inactivator Proteins; D015843:Serpins; D014867:Water; D012697:Serine Endopeptidases