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Cysteine 116 participates in intermolecular bonding of the human VEGF(121) homodimer

Nicholas J Gaspar1, Rodney A Jue, Jie Hu

  • 1Scios Inc., Sunnyvale, CA 94085, USA.

Archives of Biochemistry and Biophysics
|July 20, 2002
PubMed

Insights

Vascular endothelial growth factor (VEGF) has a previously unknown disulfide bond involving Cys116. This bond is crucial for VEGF stability but does not impact its biological activity.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Protein Chemistry

Background:

  • Vascular Endothelial Growth Factor (VEGF) is a key regulator of angiogenesis.
  • VEGF(121) is a 121-amino acid isoform of VEGF, existing as a homodimer.
  • VEGF(121) contains nine cysteine residues per monomer, with known disulfide bond formations, but the status of Cys116 remained unclear.

Purpose of the Study:

  • To elucidate the structural role and functional significance of the ninth cysteine residue (Cys116) in human VEGF(121).
  • To investigate the oxidative state of Cys116 and its impact on VEGF(121) structure and biological activity.

Main Methods:

  • Characterization of human VEGF(121) using biochemical and biophysical techniques.
  • Isolation and analysis of VEGF(121) variants with altered Cys116 states.
  • Assessment of binding and proliferation activities of modified VEGF(121) molecules.

Main Results:

  • Human VEGF(121) forms a third interchain disulfide bond between Cys116 residues of each monomer.
  • A VEGF(121) variant with additional cysteines linked to Cys116 was identified.
  • Cys116 is not found in a reduced state; selective reduction of the Cys116 disulfide bond leads to rapid reoxidation and molecular instability.
  • The oxidative state of Cys116 does not affect VEGF(121) binding or proliferation activities.

Conclusions:

  • A critical interchain disulfide bond involving Cys116 stabilizes VEGF(121).
  • While essential for structural integrity, Cys116 oxidation state does not influence VEGF(121) receptor binding or mitogenic function.
  • The Cys116 disulfide bond plays a significant role in maintaining the overall stability of the VEGF(121) molecule.

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