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

Polastro, Enrico; Deconinck, Marc Melchior; M, Devogel; Mailier, E.L.; Looze, Yvan; Schnek, Arthur G.; Léonis, J

doi:10.1016/0014-5793(78)80088-x

Cited by 25 publications

(5 citation statements)

References 21 publications

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“…The trimethylation of Lys(#, consistent with previous observations [8,21], is without any effect (compare native yeast cytochrome c with recombinant yeast protein expressed in bacteria, where trimethylation did not occur). Substitutions K72A and K72G, as well as K72R and K72L (results not shown), did not influence the electron transfer efficiency of the horse cytochrome c.…”

Section: Efficiency In the Respiratory Chainsupporting

confidence: 90%

A cytochrome c mutant with high electron transfer and antioxidant activities but devoid of apoptogenic effect

et al. 2002

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A cytochrome c mutant lacking apoptogenic function but competent in electron transfer and antioxidant activities has been constructed. To this end, mutant species of horse and yeast cytochromes c with substitutions in the N-terminal alpha-helix or position 72 were obtained. It was found that yeast cytochrome c was much less effective than the horse protein in activating respiration of rat liver mitoplasts deficient in endogenous cytochrome c as well as in inhibition of H(2)O(2) production by the initial segment of the respiratory chain of intact rat heart mitochondria. The major role in the difference between the horse and yeast proteins was shown to be played by the amino acid residue in position 4 (glutamate in horse, and lysine in yeast; horse protein numbering). A mutant of the yeast cytochrome c containing K4E and some other "horse" modifications in the N-terminal alpha-helix, proved to be (i) much more active in electron transfer and antioxidant activity than the wild-type yeast cytochrome c and (ii), like the yeast cytochrome c, inactive in caspase stimulation, even if added in 400-fold excess compared with the horse protein. Thus this mutant seems to be a good candidate for knock-in studies of the role of cytochrome c-mediated apoptosis, in contrast with the horse K72R, K72G, K72L and K72A mutant cytochromes that at low concentrations were less active in apoptosis than the wild-type, but were quite active when the concentrations were increased by a factor of 2-12.

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Section: Efficiency In the Respiratory Chainsupporting

confidence: 90%

A cytochrome c mutant with high electron transfer and antioxidant activities but devoid of apoptogenic effect

et al. 2002

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“…Trimethylation of lysine in cyt c is a post-translational modification event that takes place in fungi and higher plants. Its functional significance is not known, but it has been speculated that it increases the affinity of yeast cyt c for the mitochondrion [39] and it is considered to be a factor in the absence of apoptotic activity in yeast cyt c [40,41]. Our observation is of a substantial decrease in affinity in the absence of trimethylation.…”

Section: Interaction Of Yeast Cyt C Variants With Phospholipid Liposomesmentioning

confidence: 48%

Cytochrome c impaled: investigation of the extended lipid anchorage of a soluble protein to mitochondrial membrane models

Kalanxhi

Wallace

2007

Biochemical Journal

124

166

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Cyt c (cytochrome c) has been traditionally envisioned as rapidly diffusing in two dimensions at the surface of the mitochondrial inner membrane when not engaged in redox reactions with physiological partners. However, the discovery of the extended lipid anchorage (insertion of an acyl chain of a bilayer phospholipid into the protein interior) suggests that this may not be exclusively the case. The physical and structural factors underlying the conformational changes that occur upon interaction of ferrous cyt c with phospholipid membrane models have been investigated by monitoring the extent of the spin state change that result from this interaction. Once transiently linked by electrostatic forces between basic side chains and phosphate groups, the acyl chain entry may occur between two parallel hydrophobic polypeptide stretches that are surrounded by positively charged residues. Alteration of these charges, as in the case of non-trimethylated (TML72K) yeast cyt c and Arg91Nle horse cyt c (where Nle is norleucine), led to a decline in the binding affinity for the phospholipid liposomes. The electrostatic association was sensitive to ionic strength, polyanions and pH, whereas the hydrophobic interactions were enhanced by conformational changes that contributed to the loosening of the tertiary structure of cyt c. In addition to proposing a mechanistic model for the extended lipid anchorage of cyt c, we consider what, if any, might be the physiological relevance of the phenomenon.

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“…Apocytochrome c is a better substrate than the holocytochrome c. In vivo studies with yeast suggest that protein synthesis is required for methylation (F AROOGUI et al 1980), however, SCOTT andMITCHELL (1969) have demonstrated a temporal separation of methylated and unmethylated cytochrome c synthesis in N eurospora. It is suggested that methylation of the apocytochromes occurs in the cytosol and the trimethylation of the lysine residues enhances association of the enzyme with the mitochondria (POLASTRO et al 1978).…”

Section: Methylationmentioning

confidence: 99%

Post-Translational Modifications

Beevers¹

1982

Nucleic Acids and Proteins in Plants I

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

Cited by 25 publications

References 21 publications

A cytochrome c mutant with high electron transfer and antioxidant activities but devoid of apoptogenic effect

A cytochrome c mutant with high electron transfer and antioxidant activities but devoid of apoptogenic effect

Cytochrome c impaled: investigation of the extended lipid anchorage of a soluble protein to mitochondrial membrane models

Post-Translational Modifications

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