Receptor-mediated Ribosome Binding to Liposomes Depends on Lipid Composition

Savitz, Adam; Meyer, David I.

doi:10.1074/jbc.272.20.13140

Cited by 8 publications

(3 citation statements)

References 25 publications

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“…The fact that the 3 H: 14 C molar ratio in the TAG produced within the microsomal lumen was slightly higher than the expected ratio of 2.0 suggests that there may have been some endogenous acyl-CoA within the lumen, which would have competed with the [ 14 C]oleoyl-CoA during the re-esterification of DAG. Furthermore, if the newly synthesized TAG had been derived from monoacylglycerol then the 3 H: 14 C ratio would be expected to be 1:2. Clearly this was not the case.…”

Section: Resultsmentioning

confidence: 99%

Evidence for Triacylglycerol Synthesis in the Lumen of Microsomes via a Lipolysis-Esterification Pathway Involving Carnitine Acyltransferases

Abo-Hashema¹,

Cake²,

Power³

et al. 1999

Journal of Biological Chemistry

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Section: Resultsmentioning

confidence: 99%

Evidence for Triacylglycerol Synthesis in the Lumen of Microsomes via a Lipolysis-Esterification Pathway Involving Carnitine Acyltransferases

Abo-Hashema¹,

Cake²,

Power³

et al. 1999

Journal of Biological Chemistry

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“…In the latter case EF-G has to be attached to the outer bacterial membrane where it may interact with FA. Ribosomes are able to interact directly with lipid membranes (8). Accordingly, detailed knowledge of FA-lipid membrane interactions is essential to understand and possibly to enhance the antimicrobial activity of FA and similar agents.…”

Section: Introductionmentioning

confidence: 99%

Interaction of Fusidic Acid with Lipid Membranes: Implications to the Mechanism of Antibiotic Activity

Falck

Hautala

Karttunen

et al. 2006

Biophysical Journal

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We have studied the effects of cholesterol and steroid-based antibiotic fusidic acid (FA) on the behavior of lipid bilayers using a variety of experimental techniques together with atomic-scale molecular dynamics simulations. Capillary electrophoretic measurements showed that FA was incorporated into fluid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine membranes. Differential scanning calorimetry in turn showed that FA only slightly altered the thermodynamic properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers, whereas cholesterol abolished all endotherms when the mole fraction of cholesterol (X(chol)) was >0.20. Fluorescence spectroscopy was then used to further characterize the influence of these two steroids on DPPC large unilamellar vesicles. In the case of FA, our result strongly suggested that FA was organized into lateral microdomains with increased water penetration into the membrane. For cholesterol/DPPC mixtures, fluorescence spectroscopy results were compatible with the formation of the liquid-ordered phase. A comparison of FA and cholesterol-induced effects on DPPC bilayers through atomistic molecular dynamics simulations showed that both FA and cholesterol tend to order neighboring lipid chains. However, the ordering effect of FA was slightly weaker than that of cholesterol, and especially for deprotonated FA the difference was significant. Summarizing, our results show that FA is readily incorporated into the lipid bilayer where it is likely to be enriched into lateral microdomains. These domains could facilitate the association of elongation factor-G into lipid rafts in living bacteria, enhancing markedly the antibiotic efficacy of FA.

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“…1. Ribosomes were then isolated by a protocol based on that described by Savitz and Meyer (19). Cells were washed twice with H 2 O and lysed in low salt buffer (50 mM Tris-Cl, pH 7.5, 25 mM potassium acetate, 5 mM magnesium acetate, and 0.67 mM phenylmethylsulfonyl fluoride) with glass beads.…”

Section: Characterization Of a Major Methyl Esterified 49-kdamentioning

confidence: 99%

A Novel Post-translational Modification of Yeast Elongation Factor 1A

Zobel-Thropp¹,

Yang²,

Machado³

et al. 2000

Journal of Biological Chemistry

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Protein methylation reactions can play important roles in cell physiology. After labeling intact Saccharomyces cerevisiae cells with S-adenosyl-L-[methyl-3 H]methionine, we identified a major methylated 49-kDa polypeptide containing [ 3 H]methyl groups in two distinct types of linkages. Peptide sequence analysis of the purified methylated protein revealed that it is eukaryotic elongation factor 1A (eEF1A, formerly EF-1␣), the protein that forms a complex with GTP and aminoacyltRNAs for binding to the ribosomal A site during protein translation. Previous studies have shown that eEF1A is methylated on several internal lysine residues to give mono-, di-, and tri-N-⑀-methyl-lysine derivatives. We confirm this finding but also detect methylation that is released as volatile methyl groups after base hydrolysis, characteristic of ester linkages. In cycloheximidetreated cells, methyl esterified eEF1A was detected largely in the ribosome and polysome fractions; little or no methylated protein was found in the soluble fraction. Because the base-labile, volatile [methyl-3 H]radioactivity of eEF1A could be released by trypsin treatment but not by carboxypeptidase Y or chymotrypsin treatment, we suggest that the methyl ester is present on the ␣-carboxyl group of its C-terminal lysine residue. From the results of pulse-chase experiments using radiolabeled intact yeast cells, we find that the N-methylated lysine residues of eEF1A are stable over 4 h, whereas the eEF1A carboxyl methyl ester has a half-life of less than 10 min. The rapid turnover of the methyl ester suggests that the methylation/demethylation of eEF1A at the Cterminal carboxyl group may represent a novel mode of regulation of the activity of this protein in yeast.Reversible covalent modification of proteins is a common mode of regulation in cell metabolism (1-3). A large number of protein phosphorylation and dephosphorylation reactions are involved in a variety of cell signaling and metabolic control reactions where specific kinases phosphorylate proteins using the ␥-phosphate group of ATP and dephosphorylation of these proteins occurs through the action of phosphatases (4). In a much smaller number of cases, methylation and demethylation reactions are also involved in cell signaling and, potentially, metabolic regulation (5). Methyltransferases use the methyl donor group on S-adenosylmethionine (AdoMet) 1 to methylate various substrates; methylesterases act to demethylate them.The yeast Saccharomyces cerevisiae contains the STE14 isoprenylcysteine methyltransferase that has been shown to methylate a wide range of proteins within the cell (6, 7). Its known substrates include the small G-proteins RAS1 and RAS2 and the secreted peptide a-factor (8 -10). The specific role of this methyltransferase is unknown, but it has been suggested that methylation of its products increases their hydrophobicity to help direct them to the membrane, decreases their rate of proteolytic degradation, and may modulate their protein-protein interactions involved in cell signaling (6).I...

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Receptor-mediated Ribosome Binding to Liposomes Depends on Lipid Composition

Cited by 8 publications

References 25 publications

Evidence for Triacylglycerol Synthesis in the Lumen of Microsomes via a Lipolysis-Esterification Pathway Involving Carnitine Acyltransferases

Evidence for Triacylglycerol Synthesis in the Lumen of Microsomes via a Lipolysis-Esterification Pathway Involving Carnitine Acyltransferases

Interaction of Fusidic Acid with Lipid Membranes: Implications to the Mechanism of Antibiotic Activity

A Novel Post-translational Modification of Yeast Elongation Factor 1A

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