Publications

• A cytochrome c methyltransferase from Crithidia oncopelti.

  Valentine J., Pettigrew G.W.

  The mitochondrial cytochrome c-557 of Crithidia oncopelti contains two lysine residues and an N-terminal proline residue that are methylated in vivo by the methyl group of methionine. The purified cytochrome can act as a methyl acceptor for a methyltransferase activity in the cell extract that use ... >> More

  The mitochondrial cytochrome c-557 of Crithidia oncopelti contains two lysine residues and an N-terminal proline residue that are methylated in vivo by the methyl group of methionine. The purified cytochrome can act as a methyl acceptor for a methyltransferase activity in the cell extract that uses S-adenosylmethionine as methyl donor. Crithidia cytochrome c-557 is by far the best substrate for this methyltransferase of those tested, in spite of the fact that methylation sites are already almost fully occupied. The radioactive uptake of [14C]methyl groups from S-adenosylmethionine occurred only at a lysine residue (-8) and the N-terminal proline residue. This methyltransferase appears to differ from that of Neurospora and yeast [Durban, Nochumson, Kim, Paik & Chan (1978) J. Biol. Chem. 253, 1427-1435; DiMaria, Polastro, DeLange, Kim & Paik (1979) J. Biol. Chem. 254, 4645-4652] in that lysine-72 of horse cytochrome c is a poor acceptor. Also, the Crithidia methyltransferase appears to be stable to carry lysine methylation much further to completion than do the enzymes from yeast and Neurospora, which produce very low degrees of methylation in native cytochromes c. << Less

  Biochem J 201:329-338(1982) [PubMed] [EuropePMC]

• Cytochrome c-specific protein-lysine methyltransferase from Neurospora crassa. Purification, characterization, and substrate requirements.

  Durban E., Nochumson S., Kim S., Paik W.K., Chan S.K.

  J Biol Chem 253:1427-1435(1978) [PubMed] [EuropePMC]

• Cytochrome c-specific protein methylase III from Neurospora crassa.

  Nochumson S., Durban E., Kim S., Paik W.K.

  A protein methylase III responsible for specifically methylating the cytochrome c in Neurospora crassa was partially characterized by using unmethylated horse heart cytochrome c as a substrate. This enzyme utilizes S-adenosyl-L-methionine as the methyl donor. An analysis of the distribution of [14 ... >> More

  A protein methylase III responsible for specifically methylating the cytochrome c in Neurospora crassa was partially characterized by using unmethylated horse heart cytochrome c as a substrate. This enzyme utilizes S-adenosyl-L-methionine as the methyl donor. An analysis of the distribution of [14C]methyl groups in the peptides obtained by chymotrypsin digestion of the enzymically methylated cytochrome c showed that all of the radioactivity could be recovered within a single peak after chromatography. This indicates that the enzyme methylates a specific amino acid sequence within cytochrome c. On hydrolysis of the radioactive chymotryptic peptide, Me-14C-labelled epsilon -N-mono-methyl-lysine, epsilon-N-dimethyl-lysine and epsilon-N-trimethyl-lysine were identified. The enzyme can easily be extracted from the N. crassa mycelial pads and was purified approx. 30-fold. << Less

  Biochem J 165:11-18(1977) [PubMed] [EuropePMC]

• Cytochrome c methyltransferase, Ctm1p, of yeast.

  Polevoda B., Martzen M.R., Das B., Phizicky E.M., Sherman F.

  Cytochromes c from plants and fungi, but not higher animals, contain methylated lysine residues at specific positions, including for example, the trimethylated lysine at position 72 in iso-1-cytochrome c of the yeast Saccharomyces cerevisiae. Testing of 6,144 strains of S. cerevisiae, each overpro ... >> More

  Cytochromes c from plants and fungi, but not higher animals, contain methylated lysine residues at specific positions, including for example, the trimethylated lysine at position 72 in iso-1-cytochrome c of the yeast Saccharomyces cerevisiae. Testing of 6,144 strains of S. cerevisiae, each overproducing a different open reading frame fused to glutathione S-transferase, previously revealed that YHR109w was associated with an activity that methylated horse cytochrome c. We show here that this open reading frame, denoted Ctm1p, is specifically responsible for trimethylating lysine 72 of iso-1-cytochrome c. Unmethylated forms of cytochrome c but not other proteins or nucleic acids are methylated in vitro by Ctm1p produced in S. cerevisiae or Escherichia coli. Iso-1-cytochrome c purified from a ctm1-Delta strain is not trimethylated in vivo, whereas the K72R mutant form, or the trimethylated Lys-72 form of iso-1-cytochrome c, are not significantly methylated by Ctm1p in vitro. Like apocytochrome c, but in contrast to holocytochrome c, Ctm lp is located in the cytosol, consistent with the view that the natural substrate is apocytochrome c. The ctm1-Delta strain lacking the methyltransferase did not exhibit any growth defect on a variety of media and growth conditions, and the unmethylated iso-1-cytochrome c was produced at the normal level and exhibited the normal activity in vivo. Ctm1p and cytochrome c were coordinately regulated during anaerobic to aerobic transition, a finding consistent with the view that this methyltransferase evolved to act on cytochrome c. << Less

  J. Biol. Chem. 275:20508-20513(2000) [PubMed] [EuropePMC]