Chaperone SecB: Conformational changes demonstrated by circular dichroism

Abstract
The chaperone SecB, which is involved in protein export inEscherichia coli, is shown by circular dichroism measurements to contain a high content ofβ-pleated sheets. Prediction of the secondary structure of SecB is in good agreement with the observed content ofβ-sheet. In accordance with the previous studies in which changes in conformation were assessed indirectly [Randall (1992),Science 257, 241–245], here we show that the conformation of SecB changes with the concentration of salt in the milieu and also when SecB interacts with a peptide ligand.