Interaction of Apolipoprotein[a] with ApolipoproteinB-100 Cys3734 Region in Lipoprotein[a] Is Confirmed Immunochemically

Juan Guevara, Natalia V. Valentinova, Oscar Garcia, Antonio Gotto, Chao Yuh Yang, Susana Legal, John Gaubatz, James T. Sparrow

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Monospecific polyclonal antibodies (MPAbs) to apoB-100 regions Cys3734 and Cys4190 were isolated by affinity chromatography using the synthetic polypeptides, Q3730VPSSKLDFREIQIYKK3746 and G4182IYTREELSTMFIREVG4198, respectively, coupled to a hydrophilic resin. Molecular modeling and fluroescence labeling studies have suggested thai Cys67 located in kringle type 9 (LPaK9, located between residues 3991 and 4068 of the apo[a] sequence inferred by cDNA) of the apo[a] molecule is disulfide linked to Cys3734 of apoB-100 in human lipoprotein[a] (Lp[a]). This possibility has been further explored with MPAbs. Four species of MPAbs directed to a Cys3734 region of apoB-100 (3730-3746) were isolated from goat anti-human LDL serum by a combination of synthetic peptide (Q3730VPSSKLDFREIOIYKK3746) affinity chromatography and preparative electrophoresis (electrochromatography). MPAbs to the Cys4190 region of apoB- 100, a second or alternative disulfide link-site between apo[a] and apoB- 100, were also isolated using a synthetic peptide (G4182IYTREELSTMFIREVG4198) affinity resin. Results of immunoassays showed that binding of these four MPAbs to Lp[a] was significantly lower than to LDL. In contrast, MPABs to the apoB-100 region 4182-4198 which contains Cys4190, a second or alternative disulfide link-site between apo[a] and apoB- 100, displayed a less significant difference in binding to Lp[a] and LDL. These results provide additional evidence that the residues 3730-3746 of apoB-100 interact significantly with apo[a] in Lp[a], and that Cys3734 is a likely site far the disulfide bond connecting apo[a] and apoB-100.

Original languageEnglish (US)
Pages (from-to)17-25
Number of pages9
JournalProtein Journal
Volume15
Issue number1
DOIs
StatePublished - Jan 1 1996

Keywords

  • Apo[a]
  • apoB- 100
  • Cys3734
  • disulfide
  • electrochromatography
  • funnel
  • monospecific

ASJC Scopus subject areas

  • Biochemistry

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