Microperoxidases with increasing lengths of the peptide attached to the heme moiety have been isolated after proteolytic digestion of horse-heart cytochrome c (microperoxidases 6, 8, and 11) and of... Show moreMicroperoxidases with increasing lengths of the peptide attached to the heme moiety have been isolated after proteolytic digestion of horse-heart cytochrome c (microperoxidases 6, 8, and 11) and of cytochrome c(550) from Thiobacillus versutus (microperoxidase 17). The different microperoxidases catalyze the H2O2-dependent para-hydroxylation of aniline relatively efficiently but are rapidly inactivated under turnover conditions. The horse-heart cytochrome-c-derived microperoxidases have identical values for V-max but show a decrease of the K-m for aniline and a higher stability when the attached peptide is longer. The kinetic constants obtained for microperoxidase 17, differ markedly from the microperoxidases derived from horse-heart cytochrome c. Possible factors underlying the observed differences are discussed. Show less
Beeumen, J. van; Driessche, G. van; Huitema, F.; Duine, J.A.; Canters, G.W. 1993
The N-terminal processing of MADH from the bacterium T versutus and the N-terminal heterogeneity of the isolated a subunit of the alpha2beta2 protein complex was demonstrated by a combination of... Show moreThe N-terminal processing of MADH from the bacterium T versutus and the N-terminal heterogeneity of the isolated a subunit of the alpha2beta2 protein complex was demonstrated by a combination of Edman sequence analysis of an electroblotted band, in situ digested with pyroglutamate aminopeptidase, and accurate mass determination of the homogenous subunit by the technique of electrospray ionisation mass spectrometry. From this study, it appears that the corresponding gene of the alpha subunit contains 395 amino acids and that it is preceded by a leader sequence of 31 residues. Show less
Huitema, F.; Beeumen, J. van; Driessche, G. van; Duine, J.A; Canters, G.W 1993
The gene that codes for the alpha-subunit of methylamine dehydrogenase from Thiobacillus versutus, madA, was cloned and sequenced. It codes for a protein of 395 amino acids preceded by a leader... Show moreThe gene that codes for the alpha-subunit of methylamine dehydrogenase from Thiobacillus versutus, madA, was cloned and sequenced. It codes for a protein of 395 amino acids preceded by a leader sequence of 31 amino acids. The derived amino acid sequence was confirmed by partial amino acid sequencing. The start of the mature protein could not be determined by direct sequencing, since the N terminus appeared to be blocked. Instead, it was determined by electrospray mass spectrometry. Confirmation of the results was obtained by sequencing the N terminus after pyroglutamate aminopeptidase, digestion. The sequence is homologous to the Paracoccus denitrificans nucleotide sequence. A second open reading frame, called open reading frame 3, is located immediately downstream of madA. Show less
The complete amino acid sequence of the blue copper protein amicyanin of Thiobacillus versutus, induced when the bacterium is grown on methylamine, has been determined as follows:... Show moreThe complete amino acid sequence of the blue copper protein amicyanin of Thiobacillus versutus, induced when the bacterium is grown on methylamine, has been determined as follows: QDKITVTSEKPVAAADVPADAVVVGIEKMKYLTPEVTIKAGETVYWVNGEVMPHNVAFKKGIVGEDAFRGEMMTKDQAYAITFNEAGSYDYFCTPHPFMRGKVIVE. The four copper ligand residues in this 106-residue-containing polypeptide chain are His54, Cys93, His96, and Met99. The Thiobacillus amicyanin is 52% similar to the amicyanin of Pseudomonas AM1, the only other copper protein known with the same spacing between the second histidine ligand and the methionine ligand. T. versutus amicyanin contains no cysteine bridge and is more closely related to the plant copper protein plastocyanin than to the bacterial copper protein azurin. Alignment of the two known amicyanin sequences with the consensus sequence of the plastocyanins and comparison with the known three-dimensional structure of poplar leaves plastocyanin reveals that the bacterial proteins have the same overall structure with two beta-sheets packed face to face. The major structural differences between the amicyanins and the plastocyanins appear to be located in two of the five loops that connect the six identified beta-strands of the amicyanins. The first of these two loops, connecting strands F and G, contains a ligand histidine and must have a different conformation from the same loop in the plastocyanins because it is shorter by two amino acids. Further differences occur in the loop connecting the strands D and E. This loop contains only 17 residues in amicyanin whereas the corresponding loop of plastocyanin contains 25 residues. Despite these differences the amicyanins appear much closer related to the plastocyanins than to the azurins. The present findings demonstrate that the occurrence of blue copper proteins with clearly plastocyanin-like features is not restricted to photosynthetic redox chains. Show less
