scholarly journals Membrane-bound cytochromes c of a KCN-resistant mutant of an obligate methylotroph, Methylomonas sp.

1987 ◽  
Vol 51 (2) ◽  
pp. 339-347 ◽  
Author(s):  
Byung Dae YOON ◽  
Yoshiki TANI
Keyword(s):  
Resistant Mutant ◽  
Obligate Methylotroph ◽  
Cytochromes C ◽  
Membrane Bound

scholarly journals The electron-transport chains of the obligate methylotroph Methylophilus methylotrophus

1980 ◽  
Vol 192 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Andrew R. Cross ◽  
Christopher Anthony
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Redox Potentials ◽  
Obligate Methylotroph ◽  
Methylophilus Methylotrophus ◽  
Cytochrome O ◽  
Cytochromes C ◽  
Band Absorption ◽  
Membrane Bound ◽  
Α Band

The cytochrome complement of Methylophilus methylotrophus and its respiratory properties were determined during batch culture and in continuous culture under conditions of methanol-, nitrogen- and O2-limitation. About 35% of the cytochrome c produced by the bacteria was released into the growth medium, and of the remaining cytochrome c about half was membrane-bound and half was soluble. Two cytochromes c were always present on membranes (redox potentials 375mV and 310mV), and these probably correspond to the soluble cytochromes c described previously [Cross & Anthony (1980) Biochem. J.192, 421–427]. A third minor component of cytochrome c (midpoint potential 356mV) was only detected on membranes of methanol-limited bacteria. M. methylotrophus always contained two membrane-bound cytochromes b with α-band absorption maxima of about 556 and 563nm (measured at room temperature) and midpoint potentials of 110 and 60mV respectively. There appeared to be relatively more of the cytochrome b563 in methanol-limited bacteria. A third b-type cytochrome with an α-band absorption maximum at 558 (at 77K) reacted with CO and had a high midpoint redox potential (260mV); it is thus a potential oxidase and hence is called cytochrome o. The roles of these cytochromes in electron transport were confirmed by investigating the patterns of respiratory inhibition. It is proposed that two cytochromes are physiological oxidases: cytochrome a+a3, which is present only in methanol-limited conditions, and the cytochrome o, which is induced 10-fold in conditions of methanol excess. Schemes for electron transport from methanol and NAD(P)H to O2 in M. methylotrophus under various limitations are proposed. Spectra and potentiometric titrations of cytochromes in whole cells and membranes of M. methylotrophus grown under various nutrient limitations have been deposited as Supplementary Publication SUP 50111 (10 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

scholarly journals Free and membrane-bound forms of bacterial cytochrome c4

1988 ◽  
Vol 252 (2) ◽  
pp. 427-435 ◽  
Author(s):  
G W Pettigrew ◽  
K R Brown
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Azotobacter Vinelandii ◽  
Pseudomonas Stutzeri ◽  
Growth Conditions ◽  
Free Form ◽  
Aerobic Growth ◽  
Cytochromes C ◽  
Membrane Bound ◽  
Solubilized Form ◽  
Attached Form

Cytochrome c4 was isolated from cells of Pseudomonas aeruginosa, Pseudomonas stutzeri and Azotobacter vinelandii. The dihaem nature, Mr of approx. 20,000 and ferrohaem spectra in the region of the alpha- and beta-peaks define this family of cytochromes c. The behaviour of the holocytochromes in SDS was atypical, but removal of the haem groups resulted in a normal migration. In all three organisms most of the cytochrome c4 was tightly bound to the membrane, but some free cytochrome was detected. The membrane-attached cytochrome could be extracted with butanol, and this solubilized form was then indistinguishable in properties from the free form. Denitrifying rather than aerobic growth conditions hardly affected the total cytochrome c4 in the two pseudomonads, but there was slightly more free form and less membrane-attached form in denitrifying growth. The nature of the attachment of cytochrome c4 to the membrane is discussed and a model is proposed for the process of solubilization.

scholarly journals Amino acid sequence, haem-iron co-ordination geometry and functional properties of mitochondrial and bacterial c-type cytochromes

1985 ◽  
Vol 18 (2) ◽  
pp. 111-134 ◽  
Author(s):  
Hans Senn ◽  
Kurt Wüthrich
Keyword(s):  
Amino Acid ◽  
Purple Bacteria ◽  
Amino Acid Sequences ◽  
Blue Green Algae ◽  
Cytochromes C ◽  
Sulphur Bacteria ◽  
Membrane Bound ◽  
Nitrate And Nitrite ◽  
Haem Iron ◽  
Soluble C

Cytochromes are found in all biological oxidation Systems which involve transport of reducing equivalents through organized chains of membrane bound intermediates, regardless of the ultimate oxidant (Keilin, 1966; Bartsch, 1978; Meyer & Kamen, 1982). Thus, cytochromes are present not only in the aerobic mitochondrial and bac-terial respiratory chain, but are also found in much more diversified procariotic Systems, including all varieties of facultative anaerobes (nitrate and nitrite reducers), obligate anaerobes (sulphate reducers and phototrophic sulphur bacteria), facultative photoheterotrophes (phototrophic non-sulphur purple bacteria), and the photoautotrophic cyanobacteria (blue-green algae). Among the different types of cytochromes occurring in the cell, the soluble c-type cytochromes (‘class I’, Meyer & Kamen, 1982) are the most abundant and best characterized group of proteins (Bartsch, 1978; Meyer & Kamen, 1982; Dickerson & Timkovitch, 1975; Lemberg & Barrett, 1973; Salemme, 1977; Ferguson-Miller, Brautigan & Margoliash, 1979). The amino acid sequences of more than 80 mitochrondrial and close to 40 bacterial cytochromes c are known (Meyer & Kamen, 1982; Dickerson & Timkovitch, 1975; Schwartz & Dayhoff, 1976; Dayhoff & Barker, 1978).

Cytochromes and Anaerobic Sulfide Oxidation in the Purple Sulfur Bacterium Chromatium warmingii

1983 ◽  
Vol 38 (11-12) ◽  
pp. 960-967 ◽  
Author(s):  
Ursula Wermter ◽  
Ulrich Fischer
Keyword(s):  
Molecular Weight ◽  
Cytochrome C ◽  
Elemental Sulfur ◽  
Sulfide Oxidation ◽  
Sodium Dodecylsulfate ◽  
Gel Filtration ◽  
Purple Sulfur Bacterium ◽  
Cytochromes C ◽  
Membrane Bound ◽  
Reduced State

Two soluble acidic c-type cytochromes - c' and c-552 - were isolated by ion exchange :hromatography, gel filtration and ammonium sulfate fractionation. Cytochrome c' is a high-spir tochrome with maxima at 399 nm. 490 nm. and 634 nm in the oxidized form and at 550 nm. 15 nm and a characteristic shoulder at 434 nm in the reduced state. The best purity index obtained A280/A399) was 0.35. Cytochrome c' is autoxidizable, has a molecular weight of 12 000 (estimate by sodium dodecylsulfate electrophoresis), a midpoint redoxpotential of + 10 mV and an iso­electric point at pH 4.0. The reduced cytochrome c' reacts with carbon monoxide. The reaction reversible. Cytochrome c-552 shows maxima at 552 nm, 523 nm and 417 nm in the reduced for ind at 408 nm in the oxidized state. The best purity index obtained (A280/A408) was 0.94. "ytochrome c-552 has a molecular weight of 30 000 and an isoelectric point between pH 4.1 Zhromatium warmingii also contains a membrane-bound cytochrome c-552. During anaerobic sulfide oxidation, elemental sulfur and sulfate were formed at the same time. When all sulfide consumed by the cells, the remaining intracellular elemental sulfur was further oxidized to sulfate

The cytochrome complement of Haemophilus parasuis

1984 ◽  
Vol 30 (6) ◽  
pp. 763-773 ◽  
Author(s):  
D. F. Niven
Keyword(s):  
Growth Rate ◽  
Cytochrome C ◽  
Osmotic Shock ◽  
Shock Treatment ◽  
Redox Properties ◽  
Haemophilus Parasuis ◽  
Bacterial Concentration ◽  
Cytochromes C ◽  
Membrane Bound ◽  
Cytochrome Content

Spectral analyses with subcellular fractions derived from Haemophilus parasuis demonstrated that this organism could synthesize membrane-bound and soluble CO- and NO-binding c-type cytochromes in addition to the membrane-bound cytochromes d, a1, b, and c; cytochromes d, a1, and o were identified as potential oxidases. The membrane-bound and soluble CO- and NO-binding cytochromes c were not spectrally variant cytochromes c, and the redox properties of the soluble cytochrome (reducible by NADH but not by succinate or ascorbate plus N,N,N′,N′-tetramethyl-p-phenylenediamine) suggested that it, at least, was a low-potential cytochrome; up to 68% of the soluble cytochrome c could be released from the organisms by osmotic-shock treatment, demonstrating its extracytoplasmic location. The cytochrome content of H. parasuis was influenced by both the composition of the growth medium and the phase of growth; it is suggested that the bacterial concentration and growth rate, and therefore the availability of oxygen, regulated cytochrome synthesis.

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