9TGS
Cryo-EM structure of TamA
Summary for 9TGS
| Entry DOI | 10.2210/pdb9tgs/pdb |
| EMDB information | 55910 |
| Descriptor | Translocation and assembly module subunit TamA (1 entity in total) |
| Functional Keywords | escherichia coli k-12, membrane protein |
| Biological source | Escherichia coli |
| Total number of polymer chains | 1 |
| Total formula weight | 64875.02 |
| Authors | |
| Primary citation | Luo, Q.,Dong, X.,Zerang, Z.,Chen, Y.,Zhu, X.,Yang, L.,Zhang, Z.,Zhang, J.,Li, X.,Chen, H.,Ying, B.,Chang, S.,Zhou, J.,Dong, H.,Tang, X. Mechanistic insights into TAM-mediated OMP assembly in Gram-negative bacteria. Cell Rep, 45:117733-117733, 2026 Cited by PubMed Abstract: The β-barrel assembly machinery (BAM) is essential for outer membrane protein (OMP) biogenesis in Gram-negative bacteria and represents a validated target for antibiotic development. Its evolutionary relative, the translocation and assembly module (TAM), is thought to assemble OMPs but through a mechanism that remains poorly understood. Here, we present cryo-electron microscopy structures of Escherichia coli TamA and TamAB, capturing multiple conformational states. These structures reveal that the TamB C-terminal tail engages the TamA β-barrel to open its lateral gate, forming a transient hybrid β-interface and activating an extended AsmA-like periplasmic conduit that may facilitate substrate transport. Consistent with this mechanism, NanoLuc Binary Technology (NanoBiT)-based folding assays demonstrate that TamAB promotes OMP assembly more efficiently than TamA alone, with activity dependent on both lateral-gate opening and hybrid-interface formation. Together, our results define a substrate-mimetic priming mechanism that sets TAM apart from BAM and establish a structural framework for understanding OMP biogenesis. PubMed: 42507553DOI: 10.1016/j.celrep.2026.117733 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (7.75 Å) |
Structure validation
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