title: Analysis of the surface proteins of Acidithiobacillus ferrooxidans strain SP5/1 and the new, pyrite-oxidizing Acidithiobacillus isolate HV2/2, and their possible involvement in pyrite oxidation.
abstract: Two strains of rod-shaped, pyrite-oxidizing acidithiobacilli, their cell envelope structure and their interaction with pyrite were investigated in this study. Cells of both strains, Acidithiobacillus ferrooxidans strain SP5/1 and the moderately thermophilic Acidithiobacillus sp. strain HV2/2, were similar in size, with slight variations in length and diameter. Two kinds of cell appendages were observed: flagella and pili. Besides a typical Gram-negative cell architecture with inner and outer membrane, enclosing a periplasm, both strains were covered by a hitherto undescribed, regularly arranged 2-D protein crystal with p2-symmetry. In A. ferrooxidans, this protein forms a stripe-like structure on the surface. A similar surface pattern with almost identical lattice vectors was also seen on the cells of strain HV2/2. For the surface layer of both bacteria, a direct contact to pyrite crystals was observed in ultrathin sections, indicating that the S-layer is involved in maintaining this contact site. Observations on an S-layer-deficient strain show, however, that cell adhesion does not strictly depend on the presence of the S-layer and that this surface protein has an influence on cell shape. Furthermore, the presented data suggest the ability of the S-layer protein to complex Fe3+ ions, suggesting a role in the physiology of the microorganisms.
authors.affiliation: Centre for Electron Microscopy at the Institute for Anatomy, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Klingl
authors.forename: Christine
authors.initials: C
authors.lastname: Moissl-Eichinger
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wanner
authors.forename: Josef
authors.initials: J
authors.lastname: Zweck
authors.forename: Harald
authors.initials: H
authors.lastname: Huber
authors.forename: Michael
authors.initials: M
authors.lastname: Thomm
authors.forename: Reinhard
authors.initials: R
authors.lastname: Rachel
mesh_terms: D042763:Acidithiobacillus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000378:metabolism*; D005407:Flagella / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D019897:Periplasm / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013440:Sulfides / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; D012336:RNA, Ribosomal, 16S; C055764:S-layer proteins; D013440:Sulfides; C011342:pyrite; D007501:Iron