scholarly journals Two distinct azurins function in the electron-transport chain of the obligate methylotroph Methylomonas J

1989 ◽  
Vol 261 (2) ◽  
pp. 495-499 ◽  
Author(s):  
R P Ambler ◽  
J Tobari
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequences ◽  
British Library ◽  
Copper Proteins ◽  
Blue Copper Proteins ◽  
Methylamine Dehydrogenase ◽  
Obligate Methylotroph ◽  
Blue Copper ◽  
Transport Chain ◽  
The One

Methylomonas J is an obligate methylotroph although it is unable to grow on methane. Like Pseudomonas AM1, it produces two blue copper proteins when growing on methylamine, one of which is the recipient of electrons from the methylamine dehydrogenase. When grown on methanol, only the other blue copper protein is produced. We have determined the amino acid sequences of these blue copper proteins, and show that they are both true azurins. The sequences are clearly homologous to those of the proteins characterized from fluorescent pseudomonads and various species of Alcaligenes, and can be aligned with them and with each other without the need to postulate any internal insertions or deletions in the sequences. The iso-1 azurin, the one produced during both methanol and methylamine growth, shows 59-65% identity with these other azurins, whereas the iso-2 protein shows only 47-53% identity. The proteins show 52% identity with each other. The two functionally equivalent blue copper proteins from Pseudomonas AM1 belong to two sequence classes that are quite distinct from the true azurins. Detailed evidence for the amino acid sequences of the proteins has been deposited as Supplementary Publication SUP 50151 (23 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1989) 257, 5.

scholarly journals The primary structures of Pseudomonas AM1 amicyanin and pseudoazurin. Two new sequence classes of blue copper proteins

1985 ◽  
Vol 232 (2) ◽  
pp. 451-457 ◽  
Author(s):  
R P Ambler ◽  
J Tobari
Keyword(s):  
Amino Acid ◽  
Paracoccus Denitrificans ◽  
Sequence Similarity ◽  
Amino Acid Sequences ◽  
British Library ◽  
Copper Binding ◽  
Copper Proteins ◽  
Blue Copper Proteins ◽  
Blue Copper ◽  
Sequence Class

The amino acid sequences of two blue copper proteins from the pink facultative methylotroph Pseudomonas AM1 (N.C.I.B. 9133) were determined. They each consist of a single polypeptide chain and bind one copper atom. Amicyanin contains 99 and pseudoazurin 123 residues. Copper-binding sites, consisting of the side chains of two histidine, one cysteine and one methionine residues, can be recognized in each protein by analogy with azurin and plastocyanin, but the spacings of the ligand residues are different, and other sequence similarity is limited. Proteins that are in the pseudoazurin sequence class can be recognized in some strains of Alcaligenes, and probably also in Paracoccus denitrificans. Detailed evidence for the amino acid sequences of the proteins has been deposited as Supplementary Publication SUP 50130 (23 pp.) 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. (1985) 225, 5.

scholarly journals The ‘methylamine oxidase’ system of an obligate methylotroph

1989 ◽  
Vol 260 (1) ◽  
pp. 75-79 ◽  
Author(s):  
K A Auton ◽  
C Anthony
Keyword(s):  
Copper Proteins ◽  
Blue Copper Proteins ◽  
Optimum Growth ◽  
Methylamine Dehydrogenase ◽  
Obligate Methylotroph ◽  
Blue Copper ◽  
Oxidase System ◽  
High Copper

The terminal respiratory oxidase was solubilized from membranes of organism 4025, an obligate methylotroph. The partially purified oxidase is probably a cytochrome co. It does not oxidize amicyanin, but it oxidizes ‘azurin’ and cytochromes cH and cL. By using a complete ‘methylamine oxidase’ system reconstituted from pure methylamine dehydrogenase, purified oxidase and soluble blue copper proteins and cytochromes, it was confirmed that amicyanin is essential for methylamine oxidation; it could not be replaced by ‘azurin’ or cytochrome cH or cL. It was shown that the usual mediator between amicyanin and the oxidase is cytochrome cH, with ‘azurin’ able to replace it during growth at the high copper concentrations required for optimum growth of this unusual methylotroph.

scholarly journals The role of blue copper proteins in the oxidation of methylamine by an obligate methylotroph

1985 ◽  
Vol 228 (3) ◽  
pp. 719-726 ◽  
Author(s):  
S A Lawton ◽  
C Anthony
Keyword(s):  
Absorption Coefficient ◽  
Redox Potential ◽  
Absorption Maximum ◽  
Copper Proteins ◽  
Blue Copper Proteins ◽  
Blue Copper Protein ◽  
Methylamine Dehydrogenase ◽  
Obligate Methylotroph ◽  
Blue Copper ◽  
Copper Protein

Organism 4025, an obligate methylotroph, when grown on methylamine in the presence of a high concentration of copper, contained high concentrations of methylamine dehydrogenase and two blue copper proteins, amicyanin and an azurin-type protein; these were purified to homogeneity and characterized. The methylamine dehydrogenase is a basic protein (pI 8.8) and consists of light and heavy subunits (Mr 14100 and 43000; total Mr 112000). This dehydrogenase differed slightly from other methylamine dehydrogenases in its absorption spectrum and in its lack of thermal stability. Amicyanin, the more abundant blue copper protein, had an Mr of 11500, a midpoint redox potential of 294mV at pH 7.0, and a much lower isoelectric point (pI5.3) than other amicyanins. Its absorption maximum was 620 nm (7-24 nm higher than those of other amicyanins); its absorption coefficient (at 620 nm) was 3.8 mM-1 X cm-1. The ‘azurin’ (6% of the blue copper protein) had an Mr of 12500, a midpoint redox potential of 323 mV and a high isoelectric point (pI 9.4). Its absorption maximum was 620 nm, the absorption coefficient (16 mM-1 X cm-1) at this wavelength being considerably greater than that of any blue copper protein described previously. The partially-purified soluble cytochromes cH and cL were similar to those of other methylotrophs. The interactions of the purified redox proteins were investigated in order to elucidate their role in methylamine oxidation. Methylamine dehydrogenase was able to donate electrons only to amicyanin, the rate of reaction being 2.04 mmol/min per mumol of methylamine dehydrogenase; this is sufficient to account for the rate of respiration in whole bacteria. The blue copper proteins were able to react rapidly with each other and with both the soluble cytochromes c.

Synthetic models for active sites of reduced blue copper proteins: minimal geometric change between two oxidation states for fast self-exchange rate constants

2004 ◽  
Vol 7 (11) ◽  
pp. 1188-1190 ◽  
Author(s):  
Kiyoshi Fujisawa ◽  
Koyu Fujita ◽  
Tatsuya Takahashi ◽  
Nobumasa Kitajima ◽  
Yoshihiko Moro-oka ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Rate Constants ◽  
Active Sites ◽  
Oxidation States ◽  
Copper Proteins ◽  
Blue Copper Proteins ◽  
Blue Copper ◽  
Synthetic Models
Sign in / Sign up

Export Citation Format

Share Document