Sulfur-binding protein of flagella of Thiobacillus ferrooxidans

Abstract

The sulfur-binding protein of Thiobacillus ferrooxidans ATCC 23270 was investigated. The protein composition of the bacterium's cell surface changed according to the culture substrate. Sulfur-grown cells showed greater adhesion to sulfur than iron-grown cells. The sulfur-grown cells synthesized a 40-kDa surface protein which was not synthesized by iron-grown cells. The 40-kDa protein had thiol groups and strongly adhered to elemental sulfur powder. This adhesion was not disturbed by Triton X-100, which can quench hydrophobic interactions. However, adhesion was disturbed by 2-mercaptoethanol, which broke the disulfide bond. The thiol groups of the 40-kDa protein formed a disulfide bond with elemental sulfur and mediated the strong adhesion between T. ferrooxidans cells and elemental sulfur. The 40-kDa protein was located on the flagella. The location of the protein would make it possible for cells to be in closer contact with the surface of elemental sulfur powder.

Selective Inhibition of the Oxidation of Ferrous Iron or Sulfur in Thiobacillus ferrooxidans

“…1B and C) oxidation in buffer concentrations ranging from 0.01 to 0.5 M were determined. Enzymes required for iron and sulfur oxidation are differentially expressed depending on the bacterial growth substrate (14,23,37). Cells grown on ferrous iron showed only low levels of sulfur-oxidizing activities (Fig.…”

Utilization of solid ‘elemental’ sulfur by the phototrophic purple sulfur bacterium Allochromatium vinosum: a sulfur K-edge X-ray absorption spectroscopy study

“…albertensis, Bryant et al (1984) have shown that adhesion to elemental sulfur is due to an interaction between the glycocalyx of the organism and the sulfur surface. In other studies, Ohmura et al (1996) and Ramírez et al (2004) have found evidence for an outermembrane protein in Acidithiobacillus ferrooxidans (for- merly Thiobacillus ferrooxidans) which is probably involved in cell-sulfur adhesion. Extracellular polymeric substances (LPSs), which have been found in Atb.…”

Molecular Cloning, Sequencing, and Expression of omp-40 , the Gene Coding for the Major Outer Membrane Protein from the Acidophilic Bacterium Thiobacillus ferrooxidans

“…We have previously found that the expression of Omp40 and other proteins change with variations in the external medium of the bacterium, such as pH and phosphate starvation (3,16,25,33). Also, depending on the oxidizable substrate employed, outer membrane protein changes have been observed in T. ferrooxidans cells grown in ferrous iron or sulfur (7,18,23).…”

“…During bioleaching of minerals, the microorganisms have to adhere to the solid substrate (29,31). The presence of lipopolysaccharides and other external structures have been described on the surface of the gram-negative T. ferrooxidans, and the possible role of these components during bacterial attachment to the ores has been considered (4,10,14,23). A major outer membrane protein of 40 kDa (Omp40) has been previously described in T. ferrooxidans (16,28), and a possible role for the protein in forming small pores was also reported (35).…”