AUTHOR=Wallart Lisa , Ben Mlouka Mohamed Amine , Saffiedine Brahim , Coquet Laurent , Le Hung , Hardouin Julie , Jouenne Thierry , Phan Gilles , Kiefer-Meyer Marie-Christine , Girard Eric , Broutin Isabelle , Cosette Pascal 

TITLE=BacA: a possible regulator that contributes to the biofilm formation of Pseudomonas aeruginosa

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1332448

DOI=10.3389/fmicb.2024.1332448

ISSN=1664-302X

ABSTRACT=<p>Previously, we pointed out in <italic>P. aeruginosa</italic> PAO1 biofilm cells the accumulation of a hypothetical protein named PA3731 and showed that the deletion of the corresponding gene impacted its biofilm formation capacity. PA3731 belongs to a cluster of 4 genes (<italic>pa3732</italic> to <italic>pa3729</italic>) that we named <italic>bac</italic> for “Biofilm Associated Cluster.” The present study focuses on the PA14_16140 protein, i.e., the PA3732 (BacA) homolog in the PA14 strain. The role of BacA in rhamnolipid secretion, biofilm formation and virulence, was confirmed by phenotypic experiments with a <italic>bacA</italic> mutant. Additional investigations allow to advance that the <italic>bac</italic> system involves in fact 6 genes organized in operon, i.e., <italic>bacA</italic> to <italic>bacF.</italic> At a molecular level, quantitative proteomic studies revealed an accumulation of the BAC cognate partners by the <italic>bacA</italic> sessile mutant, suggesting a negative control of BacA toward the <italic>bac</italic> operon. Finally, a first crystallographic structure of BacA was obtained revealing a structure homologous to chaperones or/and regulatory proteins.</p>