PEDS Advance Access published online on October 30, 2007
Protein Engineering Design and Selection, doi:10.1093/protein/gzm055
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Solubilization of aggregation-prone heterologous proteins by covalent fusion of stress-responsive Escherichia coli protein, SlyD
Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Sungbuk-Ku, Seoul 136-713, South Korea
2 To whom correspondence should be addressed. E-mail: leejw{at}korea.ac.kr
The proteome profile of Escherichia coli BL21(DE3) generated in response to heat shock stress was analyzed by two-dimensional electrophoresis (2-DE), wherein we identified a FKBP-type peptidyl–prolyl cis–trans isomerse (PPIases), SlyD, as a stress-responsive (i.e. aggregation-resistant) protein. Even under an imposed severe stress condition where 29 out of 858 soluble proteins were totally eliminated and the synthesis levels of 171 proteins decreased over 5-fold, a 3.37-fold increase induced by heat shock treatment was observed in the synthesis level of SlyD compared with a non-stress condition. As a fusion partner, as well as solubility enhancer, SlyD facilitated folding and significantly increased the solubility of many aggregation-prone heterologous proteins in E. coli cytoplasm. SlyD was very effective in sequestering interactive surfaces of heterologous proteins associated with non-specific protein–protein interactions and the formation of inclusion bodies, most likely as a result of intrinsic folding efficiencies and/or chaperone-like activities. SlyD was also shown to be suitable for the production of a biologically active fusion mutant of Pseudomonas putida cutinase that is of considerable biotechnological and commercial interest.
Keywords: Escherichia coli BL21(DE3)/proteome/SlyD/solubility enhancer/stress response
Received July 23, 2007; revised September 8, 2007; accepted September 12, 2007.
1 These authors contributed equally to the work.