Behavior of human apolipoprotein E in aqueous solutions and at interfaces.

Yokoyama, Shinji; Kawai, Yuichi; Tsuji, Shoji; Yamamoto, Akira

doi:10.1016/s0021-9258(17)36247-6

Cited by 113 publications

(43 citation statements)

References 35 publications

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“…ApoE3 run alone (Panel A, solid line) shows an A 280 trace consistent with its formation of a tetramer under native conditions. The elution position corresponds to a molecular weight of about 225 kDa (standard curve not shown), higher than the true molecular weight (about 136 kDa) but similar to values obtained previously by gel filtration analysis of the naturally derived protein and consistent with an elongated molecule (Yokoyama et al, 1985). Panel A (dashed line) also shows the A 280 trace for Aβ alone, exhibiting only a small peak late in the chromatogram, as expected for Aβ.…”

Section: Resultssupporting

confidence: 83%

Native Complex Formation between Apolipoprotein E Isoforms and the Alzheimer's Disease Peptide Aβ

et al. 1996

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To explore whether the genetic linkage between apolipoprotein E (ApoE) alleles and susceptibility to Alzheimer's disease might be attributable to a direct molecular interaction between ApoE and the amyloid peptide A beta, we have produced ApoE variants in Escherichia coli and studied their interactions with A beta under native conditions. When incubated with A beta at 20-40 microM concentrations, all three isoforms of ApoE (2, 3, and 4) readily form complexes with A beta which can be isolated by gel filtration in native buffer. Freshly mixed ApoE and A beta generate a complex that co-migrates in gel filtration with the main A280 peak, which migrates identically to the ApoE tetramer alone. After several hours incubation, an additional, high molecular weight, soluble aggregate appears which also contains both ApoE and A beta. Neither ApoE nor A beta incubated by themselves produces high molecular weight aggregates under these conditions. Incubation of A beta with control proteins bovine serum albumin and immunoglobulin generates negligable binding in the gel filtration assay. Similar results were obtained whether A beta (1-40) or A beta (1-42) was used, and plasma-derived ApoE gave similar results to E. coli-produced material. The data are consistent with a role for ApoE-A beta interactions in modulating the development of AD. Since no major differences were observed in the behavior of the three ApoE isotypes, however, the molecular basis of the genetic trend between ApoE alleles and AD cannot be attributed to specific activity differences between the molecular forms of ApoE characterized in this study.

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Section: Resultssupporting

confidence: 83%

Native Complex Formation between Apolipoprotein E Isoforms and the Alzheimer's Disease Peptide Aβ

et al. 1996

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“…Third, APOE may attenuate the ability of other regulatory factors such as APOC2 or APOC3 to regulate LPL activity. While known to be surface active, APOE exhibits a similar collapse pressure at the air/water interface as APOA1 (which did not affect LPL activity in our study) and can be displaced from lipid surfaces by APOC3 ( 47 ). Also, the presence of APOE on microemulsions in the absence of other proteins does not inhibit LPL activity ( 41 ).…”

Section: Discussionsupporting

confidence: 53%

Apolipoprotein E content of VLDL limits LPL-mediated triglyceride hydrolysis

Whitacre

Howles

Street

et al. 2022

Journal of Lipid Research

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This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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“…At concentrations above 0.1 mg/mL, no significant protein concentration effect on ellipticity was found. Since the apparent protein concentration-dependent induction of a-helix in this range may be indicative of self-association (Gwynne et al, 1975;Yokoyama et al, 1985), the molecular weight of apoLp-III was determined by sedimentation equilibrium experiments in the analytical ultracentrifuge. At a concentration of 2.5 mg/mL, a calculated molecular mass of 15 230 Da was obtained, indicating that apoLp-III is present as a monomer.…”

Section: Resultsmentioning

confidence: 99%

Factors Affecting the Stability and Conformation of Locusta migratoria Apolipophorin III

Pm¹,

Cm²,

Oikawa³

et al. 1994

Biochemistry

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Apolipophorin III (apoLp-III) from the migratory locust, Locusta migratoria, represents the only full-length apolipoprotein whose three-dimensional structure has been solved. In the present study, spectroscopic methods have been employed to investigate the effects of deglycosylation (via endoglycosidase F treatment) and complexation with lipid on the stability and conformation of this protein. Addition of isolated lipid-free apoLp-III to sonicated vesicles of dimyristoylphosphatidylcholine (DMPC) resulted in the formation of relatively uniform disklike complexes with an average Strokes diameter of 13.5 nm. Flotation equilibrium experiments conducted in the analytical ultracentrifuge revealed a particle molecular mass of 588 500 Da. Chemical cross-linking and compositional analysis of apoLp-III.DMPC complexes indicated five apoLp-III molecules per disk and an overall DMPC:apoLp-III molar ratio of 122:1. Circular dichroism (CD) spectra of apoLp-III samples suggested a loss of alpha-helical structure upon deglycosylation, while complexation with DMPC did not significantly alter the helix content (estimated to be > 75%). Fluorescence spectroscopy revealed that the apoLp-III tryptophan fluorescence emission maximum was blue-shifted from 347 to 332 and 321 nm upon deglycosylation and complexation with DMPC, respectively. In quenching experiments with native apoLp-III, tryptophan residues were shielded from the positively charged quencher, CsCl. Increased exposure to KI, CsCl, and acrylamide was observed upon deglycosylation, whereas complexation with DMPC yielded lower Ksv values for KI and acrylamide and an increased value for CsCl versus native lipid-free apoLp-III. In guanidine hydrochloride denaturation studies monitored by CD or fluorescence, native, lipid-free apoLp-III displayed a denaturation midpoint of 0.60 M, and delta GDH2O = 5.37 kcal/mol was calculated.(ABSTRACT TRUNCATED AT 250 WORDS)

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Behavior of human apolipoprotein E in aqueous solutions and at interfaces.

Cited by 113 publications

References 35 publications

Native Complex Formation between Apolipoprotein E Isoforms and the Alzheimer's Disease Peptide Aβ

Native Complex Formation between Apolipoprotein E Isoforms and the Alzheimer's Disease Peptide Aβ

Apolipoprotein E content of VLDL limits LPL-mediated triglyceride hydrolysis

Factors Affecting the Stability and Conformation of Locusta migratoria Apolipophorin III

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