The use of protein structure/activity relationships in the rational design of stable particulate delivery systems

Abstract

The recombinant heat shock protein (18 kDa-hsp) from Mycobacterium leprae was studied as a T-epitope model for vaccine development. We present a structural analysis of the stability of recombinant 18 kDa-hsp during different processing steps. Circular dichroism and ELISA were used to monitor protein structure after thermal stress, lyophilization and chemical modification. We observed that the 18 kDa-hsp is extremely resistant to a wide range of temperatures (60% of activity is retained at 80ºC for 20 min). N-Acylation increased its ordered structure by 4% and decreased its ß-T1 structure by 2%. ELISA demonstrated that the native conformation of the 18 kDa-hsp was preserved after hydrophobic modification by acylation. The recombinant 18 kDa-hsp resists to a wide range of temperatures and chemical modifications without loss of its main characteristic, which is to be a source of T epitopes. This resistance is probably directly related to its lack of organization at the level of tertiary and secondary structures.

Functional characterization of a small heat shock protein from Mycobacterium leprae

“…Protein stability is one of the most important obstacles for successful formulation in the development of new generation vaccines [ 35 , 36 ]. sHsp18 of M. leprae was shown to be used as a successful vaccine delivery system [ 37 ]. However, the prevention of thermal inactivation of Sma I occurs only up to 40°C.…”