Permuting the PGF Signature Motif Blocks both Archaeosortase-Dependent C-Terminal Cleavage and Prenyl Lipid Attachment for the Haloferax volcanii S-Layer Glycoprotein
Abstract
For years, the S-layer glycoprotein (SLG), the sole component of many archaeal cell walls, was thought to be anchored to the cell surface by a C-terminal transmembrane segment. Recently, however, we demonstrated that the Haloferax volcanii SLG C terminus is removed by an archaeosortase (ArtA), a novel peptidase. SLG, which was previously shown to be lipid modified, contains a C-terminal tripartite structure, including a highly conserved proline-glycine-phenylalanine (PGF) motif. Here, we demonstrate that ArtA does not process an SLG variant where the PGF motif is replaced with a PFG motif ( slg G796F , F797G ). Furthermore, using radiolabeling, we show that SLG lipid modification requires the PGF motif and is ArtA dependent, lending confirmation to the use of a novel C-terminal lipid-mediated protein-anchoring mechanism by prokaryotes. Similar to the case for the Δ artA strain, the growth, cellular morphology, and cell wall of the slg G796F , F797G strain, in which modifications of additional H. volcanii ArtA substrates should not be altered, are adversely affected, demonstrating the importance of these posttranslational SLG modifications. Our data suggest that ArtA is either directly or indirectly involved in a novel proteolysis-coupled, covalent lipid-mediated anchoring mechanism. Given that archaeosortase homologs are encoded by a broad range of prokaryotes, it is likely that this anchoring mechanism is widely conserved.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 01, 2016
- Source ID
- 10.1128/jb.00849-15
Entities
People
- Benjamin A Garcia
- Daniel H. Haft
- Kelly R. Karch
- Mechthild Pohlschroder
- Mohd Farid Abdul Halim
- Yitian Zhou
Organizations
- Division of Molecular & Cellular Biosciences
- National Aeronautics and Space Administration
- National Center for Biotechnology Information
- United States Department of Defense
- University of Pennsylvania