Reduced immunogenicity of β-lactoglobulin by single amino acid substitution.

To reduce the immunogenicity of β-lactoglobulin (BLG), we prepared single amino acid substituted recombinant BLG mutants (BLG/P126A, BLG/V128D and BLG/D129A) in the methylotrophic yeast by fusion of the cDNA to the sequence coding for the α-factor signal peptide from . Isoelectric points of single amino acid substituted BLGs were lower than that of native BLG. CD spectra indicated that the secondary structure of BLG had maintained native structure in single amino acid substituted BLGs.

Environmental transition of signal-anchor sequences during membrane insertion via the endoplasmic reticulum translocon.

In biogenesis of membrane proteins on the endoplasmic reticulum, a protein-conducting channel called the translocon functions in both the membrane translocation of lumenal domains and the integration of transmembrane segments. Here we analyzed the environments of polypeptide chains during the processes by water-dependent alkylation of N-ethylmaleimide at site-directed Cys residues. Using the technique, the region embedded in the hydrophobic portion of the membrane within a signal-anchor sequence and its shortening by insertion of a Pro residue could be detected.