What distinguishes GroEL substrates from other Escherichia coli proteins?

It is unclear why some proteins need GroE for correct folding and others do not. Computational studies have shown that obligatory substrates, for example, have lower folding propensities and are more aggregation-prone (Azia et al., 2012). GroE substrates are also more conserved than other proteins and tend to utilize more optimal codons (Noivirt-Brik et al., 2007), although this latter feature is less pronounced in the case of obligatory substrates.

Currently, we are trying to convert GroE substrates into non-substrates and vice versa in order to identify features that render proteins GroE-dependent.