Authors
Barreiro Chiorato, L., Silveira Derami, M., Aroucha de Brito, J. P., de Souza, L. R., Bueno, N. F., Massirer, K. B., Benington, M. H., Sgro, G. G., Marques, M. V., Junqueira Borges, R., Talachia Rosa, L.
Abstract
Bordetella pertussis, the causative agent of whooping cough, is a reemerging public health threat. While the Tripartite Tricarboxylate Transporter (TTT) system BctCBA was previously implicated solely in citrate uptake, we demonstrate that the solute-binding protein BctC specifically binds citrate chelated with Zn2+ and Ni2+. To elucidate the molecular mechanism of this interaction, we determined the crystal structures of BctC in three states: apo, open (citrate-bound), and closed (citrate-zinc-bound), defining the structural determinants for metal-citrate recognition. Furthermore, transcriptional analyses show that bctCBA operon expression is upregulated under divalent cation limitation. Comparative analyses suggest that citrate-mediated divalent cation binding is a widespread feature among bacterial TTT homologs. Finally, in silico modeling of the full BctCBA complex predicts an elevator-type transport mechanism. Together, these findings redefine the functional scope of BctCBA, revealing a sophisticated strategy by which B. pertussis exploits organic chelators to acquire essential trace metals during infection.
Preprint server:
bioRxiv
The authors list and abstract were imported from bioRxiv on 31 Jul 2026.
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