Backbone dynamics of a cbEGF domain pair in the presence of calcium

J Mol Biol. 2000 Mar 3;296(4):1065-78. doi: 10.1006/jmbi.1999.3513.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Calcium / chemistry*
  • Cattle
  • Connective Tissue / chemistry
  • Epidermal Growth Factor / chemistry*
  • Fibrillin-1
  • Fibrillins
  • Humans
  • Magnetic Resonance Spectroscopy
  • Marfan Syndrome
  • Microfibrils / chemistry
  • Microfilament Proteins / chemistry*
  • Models, Chemical
  • Models, Molecular
  • Molecular Sequence Data
  • Motion
  • Pliability
  • Protein Structure, Tertiary
  • Time Factors

Substances

  • FBN1 protein, human
  • Fibrillin-1
  • Fibrillins
  • Microfilament Proteins
  • Epidermal Growth Factor
  • Calcium