The role of disulfide bonds in the structure and function of murine epidermal growth factor (mEGF).

A systematic study using solid phase peptide synthesis has been undertaken to examine the role of the disulfide bonds in the structure and function of mEGF. A combination of one, two and three native disulfide pair analogues of an active truncated (4-48) form of mEGF have been synthesised by replacing specific cysteine residues with isosteric a-amino-n-butyric acid (Abu). Oxidation of the peptides was performed using either conventional aerobic oxidation at basic pH, in DMSO under acidic conditions or via selective disulfide formation using orthogonal protection of the cysteine pairs.

Synthesis, 11C labeling and biological properties of derivatives of the tyrphostin AG957.

Four analogues of AG957, a known inhibitor of the tyrosine kinase p210(bcr-abl), have been synthesized and tested for their growth inhibitory effect against the BCR/ABL-positive FDrv210C cells as well as the epidermal growth factor (EGF) receptor-positive Baf/ERX cells. All compounds that can undergo oxidation to the corresponding quinone demonstrated inhibition of FDrv210C cells and Baf/ERX cells. Compounds that cannot become oxidized showed significantly less inhibition of BCR/ABL- or EGF receptor-mediated cell proliferation.

CR1/CR2 interactions modulate the functions of the cell surface epidermal growth factor receptor.

Recent crystallographic data on the isolated extracellular domain of the epidermal growth factor receptor (EGFR) have suggested a model for its activation by ligand. We have tested this model in the context of the full-length EGFR displayed at the cell surface, by introducing mutations in two regions (CR1 and CR2) of the extracellular domain thought to be critical for regulation of receptor activation. Mutations in the CR1 and CR2 domains have opposing effects on ligand binding affinity, receptor dimerization, tyrosine kinase activation, and signaling competence.