Thiobacillus versutus

There are four other proteins - stellacyanin, rusticyanin, umecyanin and ami-cyanin (Table 3) which have been fairly extensively studied. A crystal structure determination for amicyanin from Thiobacillus versutus is now under way [61]. A number of other type 1 proteins have been identified. These include pseudo-... 

Two amicyanins have been a recent focus of attention [84, 85], These are from the methylotrophic bacteria Pseudomonas AMI and Thiobacillus versutus,... 

Although crystals have been reported for two amicyanins (Petratos et al., 1988b Lim et al., 1986), the type 1 blue protein, which is an electron acceptor for methylamine dehydrogenase (Tobari and Harada, 1981 van Houweligen et al., 1989), neither study has yet been completed. The structure of methylamine dehydrogenase from Thiobacillus versutus (not a copper protein) has recently been reported (Vellieux et al., 1989). The amicyanin from P. denitrificans has actually been cocrystallized with methylamine dehydrogenase (F. S. Mathews, personal communication. 

The bacterium Thiobacillus versutus has been shown to require manganese for both growth and oxidation of thiosulfate. This organism uses a multienzyme system that includes two colorless proteins, A and B, and two c-type cytochromes to oxidize thiosulfate to sulfate. Protein A is a thiosulfate-binding protein protein... 

Reversible protonation and dissociation of the exposed His ligand have been observed in several BCP in the reduced metal-bound state. Since this protonation renders the proteins inactive, it has been characterized thoroughly (Sykes, 1985, 1991). An active site of 4.9 was determined by NMR for Cu(I) spinach plastocyanin (Markley et al., 1975). The occurrence of this process was conhrmed later by the crystal structure of reduced poplar plastocyanin at low pH (Cuss et al., 1986). Similar equilibria have been characterized in Achromobacter cycloclastes pseudoa-zurin (pA a 4.6) (Dennison et al., 1994b) and in Thiobacillus versutus ami-cyanin (pA a 6.7) (Lommen et al., 1988). In the latter system a lineshape analysis revealed that this His residue, on protonation and detachment from the copper(I) ion, fluctuates between two conformers (Lommen and Canters, 1990). 

In 1985 the existence of two new classes of bacterial blue proteins, the pseudoazurins and amicyanins, was demonstrated (28). Sequence information is available for pseudoazurin from Pseudomonas AMI (28), Achromobacter cycloclastes (29), as well as A. faecalis, for which the structure has been determined (12). The name pseudoazurin rather than cupredoxin is used here. The sequence for amicyanin, also present in Pseudomonas AMI, has been reported, and that for amicyanin from Thiobacillus versutus is being determined. Preliminary X-ray crystallographic information has been reported for amicyanin from T. versutus (30). 

Similar enzymes are known to occur in Paracoccus (Thiobacillus) versutus (Lu and Kelly, 1984a,b) and T. thioparus (Lyric and Suzuki, 1970b). The P. versutus enzyme has a molecular mass of 44 kDa and contains cytochrome c-551. The T. thioparus enzyme has one atom each of nonheme iron and molybdenum (Kessler and Rajagopalan, 1972). A membrane-bound type sulfite dehydrogenase has been obtained from Thiobacillus (Acidithiobacillus) thiooxidans JCM 7814. The enzyme has the molecular mass of 400 kDa and catalyzes the reduction of horse ferricytochrome c with sulfite (Nakamura et al., 1995, 2001). Also from Paracoccus (Thio-sphaera) pantotrophus GB17, sulfite dehydrogenase has been obtained. Its molecular mass is 190 kDa (2 x 47 kDa + 2 x 50 kDa) and it has 4 heme C molecules and 1-2 atoms of molybdenum (Quentmeier et al., 2000). Furthermore,... 

Bryant MP, Wolin EA, Wolin MJ, Wolfe RS (1967) Methanobacillus omelianskii, a symbiotic association of two species of bacteria. Arch Microbiol 59 20-31 Cammack R, Chapman A, Lu W-P, Kargouni A, Kelly DP (1989) Evidence that protein B of the thiosulfate-oxidizing system of Thiobacillus versutus contains a binuclear manganese cluster. FEBS Lett 253 239-243... 

Lu W-P, Kelly DP (1984a) Properties and role of sulphitexytochrome c oxidoreductase purified from Thiobacillus versutus (A2). J Gen Microbiol 130 1683-1692 Lu W-P, Kelly DP (1984b) Purification and characterization of two essential cytochromes of the thiosulphate-oxidizing multi-enzyme system from Thiobacillus A2 (Thiobacillus versutus) Biochim Biophys Acta 765 106-117... 

Lu W-P, Kelly DP (1988b) Respiration-driven proton translocation in Thiobacillus versutus and the role of the periplasmic thiosulphate-oxidizing enzyme system. Arch Microbiol 149 297-302... 

Vellieux FMD, Frank J Jr, Swarte MBA, Groendijk H, Duine JA, Drenth J, Hoi WGJ (1986) Purification, crystallization and preliminary X-ray investigation of quinoprotein methylamine dehydrogenase from Thiobacillus versutus. Eur J Biochem 154 383-386 Vernon LP, Kamen MD (1954) Haematin compounds in photosynthetic bacteria. J Biol Chem 211 643-662... 

Amicyanins function as electron carriers in the respiratory chains of some me-thylotrophic bacteria, e.g., Thiobacillus versutus [92]. They transfer single electrons from methylamine dehydrogenase to a cytochrome c [78] which then transfers the electron to cytochrome c oxidase. Amicyanin from Pseudomonas denitrificans has a molecular mass of 11.6 kD and contains 106 amino acid residues. Amicyanin contains one /J-sheet more than the eight of plastocyanin and pseudoazurin, the result of several additional amino acids at its N-terminus [78] (Fig. 15). Like pseudoazurin, amicyanin is found exclusively in bacteria. 

Identical residues are indicated Tv, P. versutus (formerly Thiobacillus versutus) Pd, P. denitrificans. 

---