title: Backbone dynamics of a cbEGF domain pair in the presence of calcium.
abstract: Calcium binding (cb) epidermal growth factor-like (EGF) domains are found in a wide variety of extracellular proteins with diverse functions. In several proteins, including the fibrillins (1 and 2), the low-density lipoprotein receptor, the Notch receptor and related molecules, these domains are organised as multiple tandem repeats. The functional importance of calcium-binding by EGF domains has been underscored by the identification of missense mutations associated with defective calcium-binding, which have been linked to human diseases. Here, we present (15)N backbone relaxation data for a pair of cbEGF domains from fibrillin-1, the defective protein in the Marfan syndrome. The data were best fit using a symmetric top model, confirming the extended conformation of the cbEGF domain pair. Our data demonstrate that calcium plays a key role in stabilising the rigidity of the domain pair on the pico- to millisecond time-scale. Strikingly, the most dynamically stable region of the construct is centred about the domain interface. These results provide important insight into the properties of intact fibrillin-1, the consequences of Marfan syndrome causing mutations, and the ultrastructure of fibrillins and other extracellular matrix proteins.
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Werner
authors.forename: V
authors.initials: V
authors.lastname: Knott
authors.forename: P A
authors.initials: PA
authors.lastname: Handford
authors.forename: I D
authors.initials: ID
authors.lastname: Campbell
authors.forename: A K
authors.initials: AK
authors.lastname: Downing
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000737:chemistry*; D002417:Cattle; D003238:Connective Tissue / Q000737:chemistry; D004815:Epidermal Growth Factor / Q000737:chemistry*; D000071838:Fibrillin-1; D000071837:Fibrillins; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008382:Marfan Syndrome; D020894:Microfibrils / Q000737:chemistry; D008840:Microfilament Proteins / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009038:Motion; D018583:Pliability; D017434:Protein Structure, Tertiary; D013997:Time Factors; D054392:Adipokines
chemical_list: D002118:Calcium; D004815:Epidermal Growth Factor; D000071838:Fibrillin-1; D000071837:Fibrillins; D008840:Microfilament Proteins; C000605722:FBN1 protein, human; D054392:Adipokines