The major soluble cytochromes of the obligately aerobic sulfur bacterium, Thiobacillus neapolitanus

• Published in: Archives of microbiology Vol. 141; no. 4; pp. 273 - 278
• Main Authors: TRUDINGER, P. A, MEYER, T. E, BARTSCH, R. G, KAMEN, M. D
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-05-1985; Berlin
• Subjects: Amino Acids - analysis; Bacteriology; Biological and medical sciences; Cytochrome c Group - analysis; Cytochromes - analysis; Fundamental and applied biological sciences. Psychology; Microbiology; Molecular Weight; Morphology, structure, chemical composition; Spectrophotometry, Ultraviolet; Spectrum Analysis; Thiobacillus - enzymology; Characterization; Cytochrome; Hemoprotein; Purification; Taxonomy; Thiobacillus neapolitanus; Electron transfer; Bacteria; Aerobe
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/BF00428836

Four cytochromes were isolated from soluble extracts of the aerobic sulfur bacterium, Thiobacillus neapolitanus. The two most abundant proteins were purified to homogeneity and thoroughly characterized. Cytochrome c-554 (547) is a monomeric, small molecular weight protein which is unusual in having two well-resolved alpha peaks in UV-visible absorption spectra. The redox potential is 208 mV. Native cytochrome c-549 is oligomeric, but has a subunit size of about 26,000. The yield of this protein could be improved dramatically by washing membranes with 30% ammonium sulfate, but the material solubilized by this method had a larger native molecular weight than that in the initial 0.1 M Tris-Cl extract and behaved differently on chromatography. The properties of cytochrome c-549 including subunit size and UV-visible absorption spectra are similar to mitochondrial cytochrome c1 and chloroplast cytochrome f, which suggests that it may be a modified form of the predominant membrane cytochrome. Based on cytochrome content, it is suggested that T. neapolitanus is not closely related to other thiobacilli.