Protein Design for Decreased Disorder: SHERP as an Exemplar Protein

Abstract

Disorder-to-order transitions are the basis for the promiscuity and diversity of many interactions seen in intrinsically disordered proteins (IDPs), leading to the ubiquity of intrinsic disorder in signalling and regulatory proteins - and thus their important role in many diseases. However, the complexity of IDP dynamics presents a unique challenge to the structural characterisation of these proteins and huge hurdles still exist when designing drugs to affect IDPs. Using the Small Hydrophilic Endoplasmic Reticulum Associated Protein (SHERP) from the parasite L. major, protein design principles have been applied to explore the protein's disorder-to-order transitions when in the presence of anionic lipids and detergents both computationally and in vitro. A number of mutations were identified which were predicted to significantly decrease protein disorder by both sequence-based methods and molecular dynamics. This has allowed for the design, expression and characterisation of mutant proteins by Synchrotron Radiation Circular Dichroism (SRCD) which decrease disorder while preserving key features of the wild-type ordered structure.Supported by: MRC Fellowship, BBSRC project grant, beamtime grants from ISA, ANKA.