The Structure of a Conserved Domain of TamB Reveals a Hydrophobic β Taco Fold

Inokentijs Josts, Christopher James Stubenrauch, Grishma Vadlamani, Khedidja Mosbahi, Daniel Walker, Trevor Lithgow, Rhys Grinter

Research output: Contribution to journalArticleResearchpeer-review

24 Citations (Scopus)


The translocation and assembly module (TAM) plays a role in the transport and insertion of proteins into the bacterial outer membrane. TamB, a component of this system spans the periplasmic space to engage with its partner protein TamA. Despite efforts to characterize the TAM, the structure and mechanism of action of TamB remained enigmatic. Here we present the crystal structure of TamB amino acids 963–1,138. This region represents half of the conserved DUF490 domain, the defining feature of TamB. TamB963-1138 consists of a concave, taco-shaped β sheet with a hydrophobic interior. This β taco structure is of dimensions capable of accommodating and shielding the hydrophobic side of an amphipathic β strand, potentially allowing TamB to chaperone nascent membrane proteins from the aqueous environment. In addition, sequence analysis suggests that the structure of TamB963-1138 is shared by a large portion of TamB. This architecture could allow TamB to act as a conduit for membrane proteins. In this work Josts et al. provide structural insight into the bacterial β barrel assembly protein, TamB. This structure suggests that TamB performs its function via a deep hydrophobic groove, capable of accommodating hydrophobic β strands.

Original languageEnglish
Pages (from-to)1898-1906
Number of pages9
Issue number12
Publication statusPublished - 5 Dec 2017


  • chaperone
  • Escherichia coli
  • membrane biology
  • microbiology
  • protein assembly
  • TamB
  • X-ray crystallography

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