Rapid Purification of Endotoxin-Free RTX Toxins

0507897 - MBÚ 2020 RIV CH eng J - Journal Article
Staněk, Ondřej - Mašín, Jiří - Osička, Radim - Jurnečka, David - Osičková, Adriana - Šebo, Peter
Rapid Purification of Endotoxin-Free RTX Toxins.
Toxins. Roč. 11, č. 6 (2019), č. článku 336. ISSN 2072-6651. E-ISSN 2072-6651
R&D Projects: GA ČR(CZ) GA18-18079S; GA ČR(CZ) GA19-04607S; GA ČR(CZ) GA19-12695S; GA ČR(CZ) GX19-27630X
Institutional support: RVO:61388971
Keywords : endotoxin * lipopolysaccharide * RTX toxins
OECD category: Microbiology
Impact factor: 3.531, year: 2019
Method of publishing: Open access
https://www.mdpi.com/2072-6651/11/6/336

Cytolytic leukotoxins of the repeat in toxin (RTX) family are large proteins excreted by gram-negative bacterial pathogens through the type 1 secretion system (T1SS). Due to low yields and poor stability in cultures of the original pathogens, it is useful to purify recombinant fatty-acylated RTX cytolysins from inclusion bodies produced in E. coli. Such preparations are, however, typically contaminated by high amounts of E. coli lipopolysaccharide (LPS or endotoxin). We report a simple procedure for purification of large amounts of biologically active and endotoxin-free RTX toxins. It is based on the common feature of RTX cytolysins that are T1SS-excreted as unfolded polypeptides and fold into a biologically active toxin only upon binding of calcium ions outside of the bacterial cell. Mimicking this process, the RTX proteins are solubilized from inclusion bodies with buffered 8 M urea, bound onto a suitable chromatographic medium under denaturing conditions and the contaminating LPS is removed through extensive on-column washes with buffers containing 6 to 8 M urea and 1% Triton X-100 or Triton X-114. Extensive on-column rinsing with 8 M urea buffer removes residual detergent and the eluted highly active RTX protein preparations then contain only trace amounts of LPS. The procedure is exemplified using four prototypic RTX cytolysins, the Bordetella pertussis CyaA and the hemolysins of Escherichia coli (HlyA), Kingella kingae (RtxA), and Actinobacillus pleuropneumoniae (ApxIA).
Permanent Link: http://hdl.handle.net/11104/0298859