A G1127S change in calcium-binding epidermal growth factor-like domain 13 of human fibrillin-1 causes short range conformational effects

J Biol Chem. 2001 May 18;276(20):17156-62. doi: 10.1074/jbc.M006547200. Epub 2001 Jan 31.

Abstract

Human fibrillin-1, an extracellular matrix glycoprotein, has a modular organization that includes 43 calcium-binding epidermal growth factor-like (cbEGF) domains arranged as multiple tandem repeats. A missense mutation that changes a highly conserved glycine to serine (G1127S) has been identified in cbEGF13, which results in a variant of Marfan syndrome, a connective tissue disease. Previous experiments on isolated cbEGF13 and a cbEGF13-14 pair indicated that the G1127S mutation caused defective folding of cbEGF13 but not cbEGF14. We have used limited proteolysis methods and two-dimensional NMR spectroscopy to identify the structural consequences of this mutation in a covalently linked cbEGF12-13 pair and a cbEGF12-14 triple domain construct. Protease digestion studies of the cbEGF12-13 G1127S mutant pair indicated that both cbEGF12 and 13 retained similar calcium binding properties and thus tertiary structure to the normal domain pair, because all identified cleavage sites showed calcium-dependent protection from proteolysis. However, small changes in the conformation of cbEGF13 G1127S, revealed by the presence of a new protease-sensitive site and comparative two-dimensional NOESY data, suggested that the fold of the mutant domain was not identical to the wild-type, but was native-like. Additional cleavage sites identified in cbEGF12-14 G1127S indicated further subtle changes within the mutant domain but not the flanking domains. We have concluded the following in this study. (i) Covalent linkage of cbEGF12 preserves the native-like fold of cbEGF13 G1127S and (ii) conformational effects introduced by G1127S are localized to cbEGF13. This study demonstrates that missense mutations in fibrillin-1 cbEGF domains can cause short range structural effects in addition to long range effects previously observed with a E1073K mutation in cbEGF12.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Binding Sites
  • Calcium / metabolism
  • Cloning, Molecular
  • Conserved Sequence
  • Epidermal Growth Factor / chemistry*
  • Extracellular Matrix Proteins / chemistry
  • Fibrillin-1
  • Fibrillins
  • Genetic Variation
  • Glycine
  • Humans
  • Marfan Syndrome / genetics
  • Microfilament Proteins / chemistry*
  • Microfilament Proteins / genetics
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation, Missense
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Conformation*
  • Protein Structure, Secondary
  • Recombinant Proteins / chemistry
  • Serine

Substances

  • Extracellular Matrix Proteins
  • FBN1 protein, human
  • Fibrillin-1
  • Fibrillins
  • Microfilament Proteins
  • Recombinant Proteins
  • Serine
  • Epidermal Growth Factor
  • Calcium
  • Glycine