Of minibody, camel and bacteriophage

This review describes the design process from conception through realisation and optimisation of a minibody'--a minimised antibody. The result was a proteinaceous molecule of novel fold and metal binding activity. We explain how combinatorial approaches, using phage display libraries, were used to randomise loop regions of the minibody. Variants were then selected for desired activities including in vitro inhibition of human interleukin-6 and the protease of the non-structural protein, NS3, of the hepatitis C virus. One such variant was successfully minimised further to produce a cyclic peptide with similar inhibition properties. Thus the work reviewed provides examples of two important processes in protein design and protein minimisation. We conclude by discussing the role of such studies in medical applications and small molecule drug discovery. We also highlight the potential of our work and similar techniques in the post-genomic era.