Insight into the stability and folding of oligomeric proteins is essential to the understanding of protein folding, especially since the majority of proteins found in nature are oligomeric. A deletion mutant of the GrpE protein from Escherichia coli, that contains the first 112 residues (GrpE1-112) of 197 total, is an oligomeric protein forming a tetrameric structure. A four-helix bundle structure is formed via the interaction of an alpha-helix (22 amino acids in length) from each monomer. Using both thermal and chemical (urea) denaturation studies, the GrpE1-112 protein has rather low stability with a T-m of unfolding of 37 degrees C, a C-m (urea) of 1.3 M, and a Delta G(unfolding) of 8.4 kJ mol(-1). Investigation into the folding pathway using circular dichroism (CD) stopped-flow revealed a two step process with a fast first phase (k(refolding) = 8.0 x 10(6) s(-1) M-1) forming a multimeric intermediate that possesses significant alpha-helical content followed by a slow, first order, step forming the folded tetramer. (C) 2012 Elsevier Inc. All rights reserved.