Negatively charged residues of the segment linking the enzyme and cytolysin moieties restrict the membrane-permeabilizing capacity of adenylate cyclase toxin

0464520 - MBÚ 2017 RIV GB eng J - Journal Article
Mašín, Jiří - Osičková, Adriana - Suková, Anna - Fišer, Radovan - Halada, Petr - Bumba, Ladislav - Linhartová, Irena - Osička, Radim - Šebo, Peter
Negatively charged residues of the segment linking the enzyme and cytolysin moieties restrict the membrane-permeabilizing capacity of adenylate cyclase toxin.
Scientific Reports. Roč. 6, Septemeber 1 (2016), s. 29137. ISSN 2045-2322. E-ISSN 2045-2322
R&D Projects: GA MŠMT(CZ) LO1509; GA MŠMT(CZ) LM2015064; GA ČR(CZ) GA16-05919S; GA ČR GA15-09157S; GA ČR(CZ) GA15-11851S; GA ČR(CZ) GA13-14547S
Institutional support: RVO:61388971
Keywords : BORDETELLA-PERTUSSIS CYAA * SECONDARY STRUCTURE PREDICTION * ANTIGEN-PRESENTING CELLS
Subject RIV: EE - Microbiology, Virology
Impact factor: 4.259, year: 2016

he whooping cough agent, Bordetella pertussis, secretes an adenylate cyclase toxin-hemolysin (CyaA) that plays a crucial role in host respiratory tract colonization. CyaA targets CR3-expressing cells and disrupts their bactericidal functions by delivering into their cytosol an adenylate cyclase enzyme that converts intracellular ATP to cAMP. In parallel, the hydrophobic domain of CyaA forms cation-selective pores that permeabilize cell membrane. The invasive AC and pore-forming domains of CyaA are linked by a segment that is unique in the RTX cytolysin family. We used mass spectrometry and circular dichroism to show that the linker segment forms a-helical structures that penetrate into lipid bilayer. Replacement of the positively charged arginine residues, proposed to be involved in target membrane destabilization by the linker segment, reduced the capacity of the toxin to translocate the AC domain across cell membrane. Substitutions of negatively charged residues then revealed that two clusters of negative charges within the linker segment control the size and the propensity of CyaA pore formation, thereby restricting the cell-permeabilizing capacity of CyaA. The 'AC to Hly-linking segment' thus appears to account for the smaller size and modest cell-permeabilizing capacity of CyaA pores, as compared to typical RTX hemolysins.
Permanent Link: http://hdl.handle.net/11104/0263753