2B8I
Crystal Structure and Functional Studies Reveal that PAS Factor from Vibrio vulnificus is a Novel Member of the Saposin-Fold Family
Summary for 2B8I
| Entry DOI | 10.2210/pdb2b8i/pdb |
| Descriptor | PAS factor (2 entities in total) |
| Functional Keywords | four helix bundle, lipid binding protein |
| Biological source | Vibrio vulnificus |
| Total number of polymer chains | 1 |
| Total formula weight | 8571.66 |
| Authors | Lee, J.H.,Yang, S.T.,Rho, S.H.,Im, Y.J.,Kim, S.Y.,Kim, Y.R.,Kim, M.K.,Kang, G.B.,Kim, J.I.,Rhee, J.H.,Eom, S.H. (deposition date: 2005-10-07, release date: 2006-02-14, Last modification date: 2024-03-13) |
| Primary citation | Lee, J.H.,Yang, S.T.,Rho, S.H.,Im, Y.J.,Kim, S.Y.,Kim, Y.R.,Kim, M.K.,Kang, G.B.,Kim, J.I.,Rhee, J.H.,Eom, S.H. Crystal structure and functional studies reveal that PAS factor from Vibrio vulnificus is a novel member of the saposin-fold family J.Mol.Biol., 355:491-500, 2006 Cited by PubMed Abstract: PAS factor is a novel putative bacterial secretion factor thought to induce secretion of periplasmic proteins. We solved the crystal structure of PAS factor from Vibrio vulnificus at 1.8A resolution and found it to be comprised of five alpha helices that form an antiparallel bundle with an up-and-down topology, and to adopt the saposin-fold characteristic of a family of proteins that bind to membranes and lipids. PAS factor lacks the disulfide bridge characteristic of mammalian saposin-fold proteins; in fact, it shows no sequence homology with mammalian proteins. Nevertheless, the molecular architectures are similar, and the shared propensity for membrane interaction suggests strongly that PAS factor is another member of the saposin-fold family. Analysis of the CD spectra showed that PAS factor binds to membranes directly, while measurement of calcein dye leakage showed that PAS factor interacts strongly with liposomes composed of anionic phospholipids, making them leaky, but binds very weakly with liposomes composed of zwitterionic phospholipids. Moreover, by analyzing tryptophan fluorescence emission from four single-tryptophan mutants (V10W, T22W, F35W, and L70W), we identified the putative phospholipid-binding site of PAS factor. The resultant membrane destabilization likely mediates secretion of periplasmic proteins required for the in vivo survival and pathogenesis of V.vulnificus. PubMed: 16318855DOI: 10.1016/j.jmb.2005.10.074 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.8 Å) |
Structure validation
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