An Analysis of Protein Folding Mechanisms
Peter Lyons (Biology), David Randall (Chemistry, and Brenden Cross (Physics)
An analysis of protein folding mechanisms: a biology-chemistry-physics collaboration
A protein is a linear array of amino acids that folds into a specific three-dimensional shape. This folding process is often assisted by other proteins called chaperones. Some proteins come prepackaged with parts that function as “built-in” chaperones, without which the proteins cannot fold properly. Carboxypeptidases are composed of an enzymatic domain and a non-enzymatic domain that is thought to function as a chaperone during folding. However, carboxypeptidase O (CPO) is an exception. It is composed of an enzymatic domain only, along with short amino acid segments on either side, one of which is necessary for the attachment of a glycolipid group so that CPO can be membrane attached. The role of these short segments and glycolipid group in folding, in the absence of a large folding domain, will be investigated. Recombinant DNA techniques will be used to modify CPO so that it lacks these segments. CPO will be expressed in an insect cell system and purified according to established techniques. This purified CPO will be analyzed by Fourier transform infrared (FTIR) spectroscopy to examine protein folding at the secondary structure level, with or without association with membranes, as well as by atomic force microscopy (AFM) to investigate the tertiary and quaternary (three-dimensional) shape and interactions of CPO in association with membranes. These studies will advance our understanding of protein folding and will additionally take advantage of advanced resources available at Andrews University.