Kinetically Stable Proteins (KSPs) are a specialized group of proteins characterized by a large, kinetically-controlled energy barrier to unfolding. These proteins unfold very slowly and have longer half-lives compared to non-Kinetically Stable Proteins (nonKSPs). Such hyperstability plays vital roles in certain biological and industrial systems where extended longevity even in harsh conditions is necessary.
Sodium Dodecyl Sulfate (SDS) has been shown to be an effective probe for high Kinetic Stability. While most nonKSPs unfold in the presence of SDS, KSPs are resistant and require further energy input, such as heat, to unfold in the presence of SDS. While SDS is a highly effective probe for identifying KSPs, it sets a very high threshold for defining Kinetic Stability and is unable to identify proteins that possess a significant level of stability, yet are not SDS-resistant.

This study identifies a set of mild, anionic surfactants that act as effective probes for proteins with moderate Kinetic Stability that cannot be identified by SDS alone. Identifying a new set of mild and moderate KSPs, which may play important biological and biotechnological roles, expands the characterization of kinetic stability beyond a binary system of SDS-resistance or SDS-susceptibility. Further, using these expanded set of detergents to identify various KSPs, we can establish a database of KSPs and apply bioinformatic and computational methods to assess key structural characteristics that contribute to mild, moderate, and high kinetic stability.

Structures of alternative surfactants used to identify moderate kinetically stable proteins

Evelyn Rugaber

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