On the type of linkage binding fatty acids present in brain white matter proteolipid apoprotein

Stoffyn, Pierre; Folch‐Pi, J.

doi:10.1016/s0006-291x(71)80172-9

Cited by 135 publications

(35 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two previous reports have described small lipophilic proteins (called proteolipids) that contain esterified fatty acids. One of these is a subunit of myelin (24) and the other is a subunit of the Ca2+,Mg2+ ATPase from sarcoplasm reticulum (25) (27). It is unlikely that these types of lipid-protein bonds are present in the viral glycoproteins because the amino-terminal residues have been identified as tyrosine for El and serine for E2 (28), and less than 0.1 mol of phosphate per mol of protein has been detected in these proteins (29 Because covalent peptide-lipid bonds have been detected in only a few cases, we were reluctant to initially consider a covalent linkage between the glycoprotein and lipid.…”

Section: Discussionmentioning

confidence: 99%

Evidence for covalent attachment of fatty acids to Sindbis virus glycoproteins.

Schmidt¹,

Bracha²,

Schlesinger³

1979

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

234

View full text Add to dashboard Cite

Selective binding of lipid to glycoprotein was detected when [3Hjpalmitate-labeled Sindbis virus particles or viral-infected cells were disrupted by heating with sodium dodecyl sulfate, and glycoproteins were isolated by electrophoresis in sodium dodecyl sulfate/lO% polyacrylamide gels. The smaller glycoprotein (E2) retained 2 to 3 times more labeled lipid than did the larger El glycoprotein, and the cell-associated glycoprotein precursor (PE2) bound even less lipid. No lipid was associated with the nonglycosylated glycoproteins that accumulated in infected cells treated with tunicamycin. The labeled lipid remained bound to the glycoproteins after exhaustive extraction with chloroform/methanol of virus particles, infected-cell extracts, or isolated glycoproteins, but it could be extracted by chloroform/methanol after treating glycoproteins with mild alkali. Analysis by gas/liquid chromatography showed that 60% of the label was in palmitate and the balance of label was distributed between oleate and stearate. There were approximately 2 mol of fatty acid bound per mol-of El glycoprotein. Proteolysis of the fatty acid-labeled glycoprotein with pepsin, thermolysin, and Pronase degraded the polypeptide to fragments that retained'the fatty acids in an alkali-labile state. These data suggest that a covalent attachment of fatty acid may occur during maturation of the viral glycoproteins.We have been studying the formation and processing of viralspecific proteins in tissue culture cells infected with Sindbis virus, a small enveloped RNA virus of the family togaviridae. A critical stage in the late events of replication of this virus is a proteolytic cleavage that alters the structure of one of the two viral-specific glycoproteins (1), and this reaction is essential for release of virus particles from the cell (2-5). In the process of studying the glycoprotein cleavage reaction we made the serendipitous observation that glycoproteins isolated by sodium dodecyl sulfate (NaDodSO4)/10% polyacrylamide gel electrophoresis after disruption of virus by NaDodSO4 appeared to retain small amounts of lipid (6). We have investigated this glycoprotein-lipid complex in more detail and describe our initial results in this communication.Two significant observations have emerged from these studies: (i) the lipid remained associated with glycoprotein despite strong denaturing conditions and proteolytic digestion but could be recovered as the methyl ester of fatty acid after mild alkali treatment in methanol, a procedure that also released fatty acid from proteolytic digestion products of the glycoproteins, and (ii) this binding of fatty acid was affected by changes in the glycoprotein structure. These data indicate that fatty acid may be covalently attached to viral glycoprotein and this modification may play an important role in the maturation of viral glycoprotein. Preliminary reports of this work have been presented (7,8).The publication costs of this article were defrayed in part by page charge payment. This article must there...

show abstract

Section: Discussionmentioning

confidence: 99%

Evidence for covalent attachment of fatty acids to Sindbis virus glycoproteins.

Schmidt¹,

Bracha²,

Schlesinger³

1979

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

234

View full text Add to dashboard Cite

show abstract

“…Until now a covalent bond between lipid and protein was not proven by structural analysis despite indications that e.g. in brain white matter [40] and in low-density lipoproteins [41] small amounts of fatty acids seem t o be bound as esters to protein. PurScation and structural studies on lipoproteins are usually seriously hampered by their insolubility and aggregation tendency.…”

Section: Discussionmentioning

confidence: 99%

Covalent Binding of Lipid to Protein

Hantke

Braun

1973

European Journal of Biochemistry

421

105

View full text Add to dashboard Cite

A new structure of a lipid and its covalent linkage to a protein (murein-lipoprotein of the Escherichia coli outer membrane) is described. Glycerylcysteine (S-(propane-2',3'-diol)-3-thio-2-aminopropanic acid) a t the N-terminal end of the polypeptide chain is the attachment site of two ester-bound fatty acids. An additional fatty acid is bound as amide to the N-terminal group.The diglyceride residue on the cysteine could be derived from the phospholipid pathway since the fatty acid composition is very similar to that of the phospholipids from the same cells. I n contrast, 65O/, of the amide-linked fatty acid is palmitate. The main fatty acids are palmitic acid (53O/,), cis-vaccenic acid (20.7 O/,), 9,lO-methylene-hexadecanoic acid (10.6O/,) and palmitoleic acid The cell wall of bacteria with the exception of some very halophilic species [l] contains a so-called rigid layer which is made up of polysaccharide chains cross-linked by short peptide bridges [2,5,50]. It is called murein, peptidoglycan, muco-or glycopeptide. I n Escherichia coli and closely related Enterobacteriaceae [6,7] about lo6 lipoprotein molecules are covalently bound to tbe polysaccharide-peptide macromolecule. The total giant macromolecule is henceforth called murein-lipoprotein complex. The complete determination of the amino acid sequence of the lipoprotein [8,9] showed that the protein molecules are bound on average to every 10 th-12 t h diaminopimelate residue of the murein by the Cterminal lysine and that the N-terminal end is probably blocked by a covalently bound lipid. All amino acid positions except the termini could be determined by conventional sequence analysis which made binding of lipid to amino-acid side-chains a t internal sites of the polypeptide chain unlikely. I n a short communication [lo] we reported that a peptide containing the total lipid present in the lipoprotein could be isolated from a digest of the lipoprotein with proteases. This pointed to a single attachment site of the lipid. About three fatty acid residues were determined per mole of lipoprotein. No glycerol or phosphate could be found which ruled out an ordinary phospholipid. Efforts were therefore directed towards identifying a compound which could link three fatty acid residues to the polypeptide chain. This paper describes the identification of this compound, the structure of the lipid and its attachment site to the protein. MATERIALS AND METHODSGrowth and Labeling of Bacteria E. coli B/r were grown by E. Merck (Darmstadt) in a glucose-salt medium enriched with lo/, yeast extract to the late logarithmic growth phase and kept frozen a t -60 "C until used. E. coli W7 (dap-, Zys-), a derivative of E. coli W173-25 [ll] is a double mutant unable to synthesize and to decarboxylate diamino-

show abstract

“…Although the specific function of this tetraspan membrane protein is unclear, its physiological importance is demonstrated by the requirement of normal PLP synthesis during myelination (16). PLP contains between 2 and 3 mol of fatty acids, mainly palmitic, oleic, and stearic acid (17), which are bound to several intracellular cysteine residues via labile thioester linkages (18 -20). Studies employing [ 3 H]palmitate have shown that the attachment of fatty acid to the polypeptide backbone takes place close to or within the myelin membrane (21,22).…”

mentioning

confidence: 99%

Palmitoylation of Proteolipid Protein from Rat Brain Myelin Using Endogenously Generated 18O-Fatty Acids

Tetzloff

Bizzozero

1998

Journal of Biological Chemistry

View full text Add to dashboard Cite

Proteolipid protein (PLP), the major protein of central nervous system myelin, contains covalently bound fatty acids, predominantly palmitic acid. This study adapts a stable isotope technique (Kuwae, T., Schmid, P. C., Johnson, S. B., and Schmid, H. O. (1990) J. Biol. Chem. 265, 5002-5007) to quantitatively determine the minimal proportion of PLP molecules which undergo palmitoylation. In these experiments, brain white matter slices from 20-day-old rats were incubated for up to 6 h in a physiological buffer containing 50% H 2 18 O. The uptake of 18 O into the carbonyl groups of fatty acids derived from PLP, phospholipids, and the free fatty acid pool was measured by gas-liquid chromatography/mass spectrometry of the respective methyl esters. Palmitic acid derived from PLP acquired increasing amounts of 18 O, ending with 2.9%18 O enrichment after 6 h of incubation.18 O incorporation into myelin free palmitic acid also increased over the course of the incubation (67.2% 18 O enrichment). After correcting for the specific activity of the 18 O-enriched free palmitic acid pool, 7.6% of the PLP molecules were found to acquire palmitic acid in 6 h. This value is not only too large to be the result of the palmitoylation of newly synthesized PLP molecules, it was also unchanged upon the inhibition of protein synthesis with cycloheximide.18 O enrichment in less actively myelinating 60-day-old rats was significantly reduced. In conclusion, our experiments suggest that a substantial proportion of PLP molecules acquire palmitic acid via an acylation/deacylation cycle and that this profile changes during development.A number of integral membrane proteins are modified after their synthesis by the covalent attachment of long-chain fatty acids (mostly palmitic acid) to one or more cytoplasmically oriented cysteine residues (for review, see Refs. 1-6). In the majority of the cases, the chemically bound acyl chains turn over much faster than the protein backbone, implying that palmitoylation is a regulatory modification. In fact, fatty acylation of this and other types of proteins has been shown to be modulated by physiological (7-9) or pharmacological stimuli (10 -14). To date, the metabolic features of palmitoylation have only been studied by labeling cultured cells with [ 3 H]palmitic acid, and the half-life of the palmitate has been estimated from the disappearance of the protein-bound radioactivity after isotopic dilution with the unlabeled fatty acid. Unfortunately, labeling experiments using [ 3 H]palmitic acid are difficult to interpret, particularly when considering the possibility that exogenous and endogenous palmitate may not have equal access to the fatty acid donor pools. Furthermore, since the specific radioactivity of the donor pool of palmitate used for protein palmitoylation cannot be estimated, it is not possible to determine the number of protein molecules participating in such rapid deacylation-reacylation cycles. Consequently, the radioactivity that becomes associated with a polypeptide during the course of an...

show abstract

On the type of linkage binding fatty acids present in brain white matter proteolipid apoprotein

Cited by 135 publications

References 6 publications

Evidence for covalent attachment of fatty acids to Sindbis virus glycoproteins.

Evidence for covalent attachment of fatty acids to Sindbis virus glycoproteins.

Covalent Binding of Lipid to Protein

Palmitoylation of Proteolipid Protein from Rat Brain Myelin Using Endogenously Generated 18O-Fatty Acids

Contact Info

Product

Resources

About