Biological significance of methylation of cytochromes from ascomycetes and plants

Polastro, Enrico; Looze, Yvan; Léonis, J

doi:10.1016/s0031-9422(00)89221-3

Cited by 19 publications

(6 citation statements)

References 19 publications

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“…The two forms showed the same redox potentials, autooxidation parameters and capacity to serve as substrates to cytochrome c oxidase, cytochrome c peroxidase and succinate cytochrome c oxidoreductase [9]. Kinetics of digestion by protease A and B of baker's yeast and by trypsin were identical for the two forms (Polastro, E., unpublished results).…”

Section: Introductionmentioning

confidence: 89%

Evidence that trimethylation of iso‐I‐cytochrome c from Saccharomyces cerevisiae affects interaction with the mitochondrion

Polastro¹,

Deconinck²,

M³

et al. 1978

FEBS Letters

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Section: Introductionmentioning

confidence: 89%

Evidence that trimethylation of iso‐I‐cytochrome c from Saccharomyces cerevisiae affects interaction with the mitochondrion

Polastro¹,

Deconinck²,

M³

et al. 1978

FEBS Letters

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“…Because of the ability of trypsin to cleave polypeptides at lysine residues, including methylated ones (38,39), each radioactive peptide likely contained only one lysine residue representing a site of methylation. While 16 labeled peptides from EF-la were found, 9 were more prominent and represented lysine residues preferentially methylated.…”

mentioning

confidence: 99%

Methylation of elongation factor 1 alpha from the fungus Mucor.

Hiatt

Garcia

Merrick

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

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A basic protein from the dimorphic fungus Mucor racemosus, found to be highly methylated, is shown to be protein synthesis elongation factor la. This protein is the most abundant protein in hyphal cells but is less abundant in yeast cells. It is posttranslationally methylated with the formation of mono-, di-, and trimethyllysine at as many as 16 sites. Nearly 20% of the 44 lysine residues of elongation factor la from mycelia are modified while those from sporangiospores are virtually unmethylated.Mucor racemosus is a dimorphic fungus that exists in either yeast or hyphal forms. These changes in morphology are accompanied by changes in the translational system, evidenced by an acceleration in the rate of peptide bond formation (1, 2) and by a change in the level of phosphorylation of a ribosomal protein (3). In the course of studying posttranslational modifications in the fungus, we resolved several methylated peptides by using two-dimensional polyacrylamide gel electrophoresis. We have now identified one of these peptides as the a subunit of protein synthesis elongation factor 1 (EF-la), the functional equivalent of prokaryotic elongation factor Tu (EF-Tu) (4). EFTu from Salmonella typhimurium and Escherichia coli is methylated (5, 6), and that in E. coli contains a single methyllysine at position 56.In certain proteins, acidic amino acids are methylated by a reversible carboxymethylation reaction, examples of which have been shown to play roles in bacterial chemotaxis (7-9), leukocyte chemotaxis (10-12), and hormone secretion (13). The methylation of basic amino acids occurs at the E-amino group of lysine, the guanidinium group of arginine, or the imidazole group of histidine (14). Although these reactions show a high degree of specificity, there has been no clear functional role assigned to the presence ofmethylated basic amino acids. Methylated basic amino acids occur in histones (15,16,17)

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“…Since in vitro results demonstrate only minor and possibly insignificant differences in the physical parameters (13,17) and biochemical reactivities (18) of methylated and unmethylated iso-1-cytochrome c, it appears more likely to us that the unmethylated cytochrome c is only marginally less active in vivo than the methylated form and that the absence of the methylase may not result in obvious phenotypic changes. In light of recent evidence suggesting that methylation of cytochrome c facilitates binding to mitochondria (18), our findings suggest that the lowered binding efficiency of the unmethylated form would be insufficient to produce a cyc mutant phenotype. Lacking a mutant deficient in cytochrome c-specific methylase and therefore information concerning the phenotype of such a mutant, the role of trimethylation of cytochrome c remains speculative.…”

Section: Discussionmentioning

confidence: 47%

“…The biological function of cytochrome c methylation is unknown. Measurement of the stabilities toward denaturants (17), circular dichroic spectra (13), and kinetic parameters in reactions with cytochrome c peroxidase, oxidase, and succinate oxidoreductase (18) showed only minor, if any, differences between the methylated and unmethylated yeast iso-1-cytochromes c. However, recent evidence suggests that trimethylated iso-1-cytochrome c does have a greater affinity for mitochondria than does the unmethylated form (19); although the in vivo significance of this finding is unclear, it suggested that the lack of such modification may express itself phenotypically as impaired cytochrome c function. Therefore, in the investigation reported here, cyc mutants of yeast, which are deficient in cytochrome c levels and activities (7,23,27,28), were screened for cytochrome c methylase activity, with the goal of possibly identifying a methylase-deficient strain among the cyc mutants and demonstrating a role for the modification in vivo.…”

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confidence: 99%

Yeast cytochrome c-specific protein-lysine methyltransferase: coordinate regulation with cytochrome c and activities in cyc mutants

Liao¹,

Sherman²

1979

J Bacteriol

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The cytochromes c of fungi and higher plants contain one or two residues of e-N-trimethyllysine, whose biological role is unknown. A cytochrome c-specific Sadenosylmethionine:protein-lysine methyltransferase (methylase) activity was shown to be present in extracts of the bakers' yeast Saccharomyces cerevisiae, and basic kinetic properties of this enzyme are described. The specific activity of the methylase was lower in extracts of cells grown under conditions of catabolite (glucose) repression or anaerobiosis where cytochrome c levels were low, compared with cells grown under derepressed conditions where cytochrome c levels were high. During anaerobic-to-aerobic adaptation, the methylase was induced in parallel with cytochrome c, thus suggestiDng that the syntheses of cytochrome c and cytochrome c methylase are coordinately regulated. None of the cyc strains surveyed (cycl, cyc2, cyc3, cyc4, cyc5, and cyc6) had diminished levels of methylase, although some of them were completely or almost completely deficient in cytochrome c.

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Biological significance of methylation of cytochromes from ascomycetes and plants

Cited by 19 publications

References 19 publications

Evidence that trimethylation of iso‐I‐cytochrome c from Saccharomyces cerevisiae affects interaction with the mitochondrion

Evidence that trimethylation of iso‐I‐cytochrome c from Saccharomyces cerevisiae affects interaction with the mitochondrion

Methylation of elongation factor 1 alpha from the fungus Mucor.

Yeast cytochrome c-specific protein-lysine methyltransferase: coordinate regulation with cytochrome c and activities in cyc mutants

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