In situ protein folding and activation in bacterial inclusion bodies.
Recent observations indicate that bacterial inclusion bodies formed in absence of the main chaperone DnaK result largely enriched in functional, properly folded recombinant proteins. Unfortunately, the molecular basis of this intriguing fact, with obvious biotechnological interest, remains unsolved. We have explored here two non-excluding physiological mechanisms that could account for this observation, namely selective removal of inactive polypeptides from inclusion bodies or in situ functional activation of the embedded proteins. By combining structural and functional analysis, we have not observed any preferential selection of inactive and misfolded protein species by the dissagregating machinery during inclusion body disintegration. Instead, our data strongly support that folding intermediates aggregated as inclusion bodies could complete their natural folding process once deposited in protein clusters, which conduces to significant functional activation. In addition, in situ folding and protein activation in inclusion bodies is negatively regulated by the chaperone DnaK.
Gonzalez-Montalban
Nuria
N
Institute for Biotechnology and Biomedicine, Department of Genetics and Microbiology, Autonomous University of Barcelona and CIBER-BBN Network in Bioengineering, Biomaterials and Nanomedicine, Bellaterra, 08193 Barcelona, Spain.
Natalello
Antonino
A
García-Fruitós
Elena
E
Villaverde
Antonio
A
Doglia
Silvia Maria
SM
D036022:Capsid Proteins / Q000032:analysis / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D002479:Inclusion Bodies / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D017510:Protein Folding; D021381:Protein Transport / Q000235:genetics; D001616:beta-Galactosidase / Q000032:analysis / Q000378:metabolism
D036022:Capsid Proteins; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; C442501:VP1 protein, Foot-and-mouth disease virus; D001616:beta-Galactosidase; C063842:dnaK protein, E coli