The AAA+ molecular chaperone Hsp104 mediates the extraction of proteins from aggregates by unfolding and threading them through its axial channel in an ATP-driven process. An Hsp104-binding peptide selected from solid phase arrays enhanced the refolding of a firefly luciferase-peptide fusion protein. Analysis of peptide binding using tryptophan fluorescence revealed two distinct binding sites, one in each AAA+ module of Hsp104.
View Article and Find Full Text PDFCalnexin and calreticulin are molecular chaperones of the endoplasmic reticulum (ER) whose folding-promoting functions are directed predominantly toward aspargine-linked glycoproteins. This is a consequence of calnexin and calreticulin being lectins with specificity for the early oligosaccharide (OS)-processing intermediate, Glc1Man9GlcNAc2. In addition, they interact with non-native conformers of glycoprotein polypeptide chains to prevent aggregation and recruit the thiol oxidoreductase ERp57 to catalyze glycoprotein disulfide formation/isomerization.
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