4P94

The crystal structure of the soluble domain of Sulfolobus acidocaldarius FlaF (residues 35-164)

Summary for 4P94

• Entry DOI: 10.2210/pdb4p94/pdb
• Descriptor: Conserved flagellar protein F, SODIUM ION (3 entities in total)
• Functional Keywords: immunoglobulin-like beta-sandwich, motor protein
• Biological source: Sulfolobus acidocaldarius
• Total number of polymer chains: 2
• Total formula weight: 32520.71

Authors

Tsai, C.-L.,Arvai, A.S.,Ishida, J.P.,Tainer, J.A. (deposition date: 2014-04-02, release date: 2015-04-22, Last modification date: 2023-09-27)

Primary citation

Banerjee, A.,Tsai, C.L.,Chaudhury, P.,Tripp, P.,Arvai, A.S.,Ishida, J.P.,Tainer, J.A.,Albers, S.V.
FlaF Is a beta-Sandwich Protein that Anchors the Archaellum in the Archaeal Cell Envelope by Binding the S-Layer Protein.
Structure, 23:863-872, 2015

PubMed Abstract: Archaea employ the archaellum, a type IV pilus-like nanomachine, for swimming motility. In the crenarchaeon Sulfolobus acidocaldarius, the archaellum consists of seven proteins: FlaB/X/G/F/H/I/J. FlaF is conserved and essential for archaellum assembly but no FlaF structures exist. Here, we truncated the FlaF N terminus and solved 1.5-Å and 1.65-Å resolution crystal structures of this monotopic membrane protein. Structures revealed an N-terminal α-helix and an eight-strand β-sandwich, immunoglobulin-like fold with striking similarity to S-layer proteins. Crystal structures, X-ray scattering, and mutational analyses suggest dimer assembly is needed for in vivo function. The sole cell envelope component of S. acidocaldarius is a paracrystalline S-layer, and FlaF specifically bound to S-layer protein, suggesting that its interaction domain is located in the pseudoperiplasm with its N-terminal helix in the membrane. From these data, FlaF may act as the previously unknown archaellum stator protein that anchors the rotating archaellum to the archaeal cell envelope.

PubMed: 25865246
DOI: 10.1016/j.str.2015.03.001

Experimental method

X-RAY DIFFRACTION (1.651 Å)