{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"omics_type":["Unknown"],"volume":["14"],"submitter":["Yoshimoto S"],"pubmed_abstract":["Trimeric autotransporter adhesins (TAAs) are outer membrane (OM) proteins that are widely distributed in gram-negative bacteria and are involved primarily in adhesion to biotic and abiotic surfaces, cell agglutination, and biofilm formation. TAAs consist of a passenger domain, which is secreted onto the cell surface, and a transmembrane domain, which forms a pore in the OM to secrete and anchor the passenger domain. Because the interactions between TAAs and chaperones or dedicated auxiliary proteins during secretion are short-lived, TAAs are thought to reside on the OM without forming complexes with other proteins after secretion. In this study, we aimed to clarify the interactions between an <i>Acinetobacter</i> TAA, AtaA, and a peptidoglycan (PG)-binding periplasmic protein, TpgA. Pull-down assays using recombinant proteins identified the interacting domains. X-ray crystallography at 2.6 Å resolution revealed an A3B3 heterohexameric complex structure composed of the N-terminal domain of TpgA and the transmembrane domain of AtaA. TpgA-N consists of two short α helices and three antiparallel β strands, yielding an ααβββ topology similar to BamE. However, the regions corresponding to BamE interfaces with BamA and BamD differ in TpgA-N. All-atom molecular dynamics simulations and mutational assays revealed that both electrostatic and hydrophobic interactions contribute to stable complex formation. Bioinformatic analyses indicate that the TAA-TpgA complex occurs in a wide range of species. These findings will contribute to a better understanding of TAAs and the cell envelope."],"journal":["Cell surface (Amsterdam, Netherlands)"],"pagination":["100155"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC12523085"],"repository":["biostudies-literature"],"pubmed_title":["Insights into the complex formation of a trimeric autotransporter adhesin with a peptidoglycan-binding periplasmic protein."],"pmcid":["PMC12523085"],"pubmed_authors":["Suzuki A","Kanie J","Koiwai K","Hori K","Lupas AN","Sasahara J","Yoshimoto S"],"additional_accession":[]},"is_claimable":false,"name":"Insights into the complex formation of a trimeric autotransporter adhesin with a peptidoglycan-binding periplasmic protein.","description":"Trimeric autotransporter adhesins (TAAs) are outer membrane (OM) proteins that are widely distributed in gram-negative bacteria and are involved primarily in adhesion to biotic and abiotic surfaces, cell agglutination, and biofilm formation. TAAs consist of a passenger domain, which is secreted onto the cell surface, and a transmembrane domain, which forms a pore in the OM to secrete and anchor the passenger domain. Because the interactions between TAAs and chaperones or dedicated auxiliary proteins during secretion are short-lived, TAAs are thought to reside on the OM without forming complexes with other proteins after secretion. In this study, we aimed to clarify the interactions between an <i>Acinetobacter</i> TAA, AtaA, and a peptidoglycan (PG)-binding periplasmic protein, TpgA. Pull-down assays using recombinant proteins identified the interacting domains. X-ray crystallography at 2.6 Å resolution revealed an A3B3 heterohexameric complex structure composed of the N-terminal domain of TpgA and the transmembrane domain of AtaA. TpgA-N consists of two short α helices and three antiparallel β strands, yielding an ααβββ topology similar to BamE. However, the regions corresponding to BamE interfaces with BamA and BamD differ in TpgA-N. All-atom molecular dynamics simulations and mutational assays revealed that both electrostatic and hydrophobic interactions contribute to stable complex formation. Bioinformatic analyses indicate that the TAA-TpgA complex occurs in a wide range of species. These findings will contribute to a better understanding of TAAs and the cell envelope.","dates":{"release":"2025-01-01T00:00:00Z","publication":"2025 Dec","modification":"2026-06-04T14:42:10.256Z","creation":"2026-05-10T03:11:43.195Z"},"accession":"S-EPMC12523085","cross_references":{"pubmed":["41103730"],"doi":["10.1016/j.tcsw.2025.100155"]}}