Almost half of the RTX domain is dispensable for complement receptor 3 binding and cell-invasive activity of the Bordetella adenylate cyclase toxin

0544756 - MBÚ 2022 RIV US eng J - Journal Article
Espinosa-Vinals, Carlos Angel - Mašín, Jiří - Holubová, Jana - Staněk, Ondřej - Jurnečka, David - Osička, Radim - Šebo, Peter - Bumba, Ladislav
Almost half of the RTX domain is dispensable for complement receptor 3 binding and cell-invasive activity of the Bordetella adenylate cyclase toxin.
Journal of Biological Chemistry. Roč. 297, č. 1 (2021), č. článku 100833. ISSN 0021-9258. E-ISSN 1083-351X
R&D Projects: GA ČR(CZ) GA19-15175S; GA ČR(CZ) GA19-04607S; GA ČR(CZ) GX19-27630X; GA MŠMT(CZ) LM2018133
Institutional support: RVO:61388971
Keywords : identification * translocation * secretion * acylation * membrane * delivery
OECD category: Microbiology
Impact factor: 5.485, year: 2021
Method of publishing: Open access
https://www.webofscience.com/wos/woscc/full-record/WOS:000678068400033

The whooping cough agent Bordetella pertussis secretes an adenylate cyclase toxin (CyaA) that through its large carboxy-proximal Repeat-in-ToXin (RTX) domain binds the complement receptor 3 (CR3). The RTX domain consists of five blocks (I-V) of characteristic glycine and aspartate-rich nonapeptides that fold into five Ca2+-loaded parallel beta-rolls. Previous work indicated that the CR3-binding structure comprises the interface of beta-rolls II and III. To test if further portions of the RTX domain contribute to CR3 binding, we generated a construct with the RTX block II/III interface (CyaA residues 1132-1294) linked directly to the C-terminal block V fragment bearing the folding scaffold (CyaA residues 1562-1681). Despite deletion of 267 internal residues of the RTX domain, the Ca2+-driven folding of the hybrid block III/V beta-roll still supported formation of the CR3-binding structure at the interface of beta-rolls II and III. Moreover, upon stabilization by N- and C-terminal flanking segments, the block III/V hybrid-comprising constructs competed with CyaA for CR3 binding and induced formation of CyaA toxin-neutralizing antibodies in mice. Finally, a truncated CyaA.1295- 1561 toxin bound and penetrated erythrocytes and CR3-expressing cells, showing that the deleted portions of RTX blocks III, IV, and V (residues 1295-1561) were dispensable for CR3 binding and for toxin translocation across the target cell membrane. This suggests that almost a half of the RTX domain of CyaA is not involved in target cell interaction and rather serves the purpose of toxin secretion.
Permanent Link: http://hdl.handle.net/11104/0321577