title: Effects of ionic strength on inclusion body refolding at high concentration.
abstract: For commercial applications refolding process must be fast, inexpensive and highly efficient. In the past many strategies for protein refolding were introduced. Still, simple refolding methods with high product concentrations are still rare. Refolding experiments were performed with fructosyltransferase (FTF, EC 2.4.1.162) from Bacillus subtilis NCIMB 11871 produced as inclusion bodies. Solubilizates were refolded with batch dialysis or by continuous exchange of dialysis buffers with variable ionic strength. By employing dialysis with gentle removal of denaturant the dependence of protein concentration and decreasing refolding yields could be overcome compared to batch dialysis and yields were enhanced by 52% at protein concentrations of approx. 10 mg/mL. The average specific activity of refolded FTF was 123 U/mg, 83% relative to standard FTF. Rising ionic strength of refolding buffers to 600 mM leads to complete renaturation of solubilized protein at equal protein concentration. Buffer composition plays a less significant role on renaturation output. The effect might be correlated with ion charge density of co-solvents.
authors.affiliation: Institute of Technical Chemistry, Section of Carbohydrate Technology, Technical University Braunschweig, Hans-Sommer-Straße 10, D-38106 Braunschweig, Germany. Electronic address: j.gabrielczyk@tu-braunschweig.de.
authors.forename: Jakub
authors.initials: J
authors.lastname: Gabrielczyk
authors.affiliation: Institute of Technical Chemistry, Section of Carbohydrate Technology, Technical University Braunschweig, Hans-Sommer-Straße 10, D-38106 Braunschweig, Germany. Electronic address: jonas.kluitmann@tu-braunschweig.de.
authors.forename: Jonas
authors.initials: J
authors.lastname: Kluitmann
authors.affiliation: Institute of Physical and Theoretical Chemistry, Section of NanoBioSciences, Technical University Braunschweig, Hans-Sommer-Straße 10, D-38106 Braunschweig, Germany. Electronic address: t.dammeyer@tu-braunschweig.de.
authors.forename: Thorben
authors.initials: T
authors.lastname: Dammeyer
authors.affiliation: Institute of Technical Chemistry, Section of Carbohydrate Technology, Technical University Braunschweig, Hans-Sommer-Straße 10, D-38106 Braunschweig, Germany. Electronic address: a.joerdening@tu-braunschweig.de.
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Jördening
mesh_terms: D001412:Bacillus subtilis / Q000737:chemistry / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006602:Hexosyltransferases / Q000737:chemistry* / Q000235:genetics; D002479:Inclusion Bodies / Q000737:chemistry*; D009994:Osmolar Concentration; D058849:Protein Refolding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D006602:Hexosyltransferases; C021451:inulosucrase
keywords: Dialysis; E. coli; Inclusion body; Ionic strength; Protein refolding