skip to main content

DOE PAGESDOE PAGES

Title: FlaF is a β-sandwich protein that anchors the archaellum in the archaeal cell envelope by binding the S-layer protein

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.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [6] ;  [3]
  1. Max Planck Institute for terrestrial Microbiology, Marburg (Germany). Molecular Biology of Archaea; Phillips Univ. Marburg, Marburg (Germany)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); The Univ. of Texas MD Anderson Cancer Center; Houston, TX (United States)
  3. Max Planck Institute for terrestrial Microbiology, Marburg (Germany). Molecular Biology of Archaea; Univ. of Freiburg, Freiburg (Germany)
  4. Univ. of Texas MD Anderson Cancer Center, Houston, TX (United States)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of Texas MD Anderson Cancer Center, Houston, TX (United States)
Publication Date:
OSTI Identifier:
1208647
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Structure
Additional Journal Information:
Journal Volume: 23; Journal Issue: 5; Journal ID: ISSN 0969-2126
Publisher:
Elsevier
Research Org:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES