A comparison of folding techniques in the chemical synthesis of the epidermal growth factor-like domain in neu differentiation factor alpha/beta.

The 52-residue alpha/beta chimera of the epidermal growth factor-like domain in neu differentiation factor (NDFealpha/beta) has been synthesized and folded to form a three disulfide bridge (Cys182-Cys196, Cys190-Cys210, Cys212-Cys221) containing peptide. We investigated two general strategies for the formation of the intramolecular disulfide bridges including, the single-step approach, which used fully deprotected and reduced peptide, and a sequential approach that relied on orthogonal cysteine protection in which specific pairs are excluded from the first oxidation step. Because there are 15 possible disulfide bridge arrangements in a peptide with six cysteines, the one-step approach may not always provide the desired disulfide pairing.

A Neu differentiation factor (NDF) domain essential for proliferation and alterations in morphology of colonic epithelial cells in vitro.

The Neu Differentiation Factors (NDFs, also termed "heregulins") are a family of proteins that were first isolated as ligands for the HER2 (ergB2, or p185neu) receptor protein tyrosine kinase. Here we show that NDF acts to stimulate the proliferation and alter the cellular morphology of colonic epithelial cells in culture. Dramatic NDF-induced changes in cellular morphology were noted in the colonic epithelial cell line, LIM 1215.

Development of highly selective SH3 binding peptides for Crk and CRKL which disrupt Crk-complexes with DOCK180, SoS and C3G.

Many Src Homology 3 (SH3) domains function as molecular adhesives in intracellular signal transduction. Based on previous ultrastructural studies, short motifs which bind to the first SH3 domains of the adapters Crk and CRKL were selectively mutagenised to generate Crk/CRKL SH3-binding peptides of very high affinity and selectivity. Affinities were increased up to 20-fold compared to the best wildtype sequences, while the selectivity against a similar SH3 domain [Grb2SH3(N)] was not only retained, but sometimes increased.

Identification of cardiac myosin peptides capable of inducing autoimmune myocarditis in BALB/c mice.

Immunization with cardiac myosin induces T cell-mediated myocarditis in genetically predisposed mice and serves as a model for autoimmune heart disease. This study was undertaken to identify pathogenic epitopes on the myosin molecule. Our approach was based on the comparison of the pathogenicity between cardiac (alpha-)myosin and soleus muscle (beta-)myosin.

Mature T cell reactivity altered by peptide agonist that induces positive selection.

Recent studies have investigated how defined peptides influence T cell development. Using a T cell receptor-transgenic beta2-microglobulin-deficient model, we have examined T cell maturation in fetal thymic organ cultures in the presence of various peptides containing single-alanine substitutions of the strong peptide agonist, p33. Cocultivation with the peptide A4Y, which contains an altered T cell contact residue, resulted in efficient positive selection.