title: Specificity determinants in the interaction of apolipoprotein(a) kringles with tetranectin and LDL.
abstract: Lipoprotein(a) is composed of low density lipoprotein and apolipoprotein(a). Apolipoprotein(a) has evolved from plasminogen and contains 10 different plasminogen kringle 4 homologous domains [KIV(1-110)]. Previous studies indicated that lipoprotein(a) non-covalently binds the N-terminal region of lipoprotein B100 and the plasminogen kringle 4 binding plasma protein tetranectin. In this study recombinant KIV(2), KIV(7) and KIV(10) derived from apolipoprotein(a) were produced in E. coli and the binding to tetranectin and low density lipoprotein was examined. Only KIV(10) bound to tetranectin and binding was similar to that of plasminogen kringle 4 to tetranectin. Only KIV(7) bound to LDL. In order to identify the residues responsible for the difference in specificity between KIV(7) and KIV(10), a number of surface-exposed residues located around the lysine binding clefts were exchanged. Ligand binding analysis of these derivatives showed that Y62, and to a minor extent W32 and E56, of KIV(7) are important for LDL binding to KIV(7), whereas R32 and D56 of KIV(10) are required for tetranectin binding of KIV(10).
authors.affiliation: Laboratory of Gene Expression, Department of Molecular and Structural Biology, Aarhus, DK-8000 Aarhus C, Denmark.
authors.forename: Nigel R
authors.initials: NR
authors.lastname: Caterer
authors.forename: Jonas H
authors.initials: JH
authors.lastname: Graversen
authors.forename: Christian
authors.initials: C
authors.lastname: Jacobsen
authors.forename: Søren K
authors.initials: SK
authors.lastname: Moestrup
authors.forename: Bent W
authors.initials: BW
authors.lastname: Sigurskjold
authors.forename: Michael
authors.initials: M
authors.lastname: Etzerodt
authors.forename: Hans C
authors.initials: HC
authors.lastname: Thøgersen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001054:Apolipoproteins A / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D002846:Chromatography, Affinity; D002847:Chromatography, Agarose; D004591:Electrophoresis, Polyacrylamide Gel; D005822:Genetic Vectors; D018082:Kringles / Q000235:genetics*; D037181:Lectins, C-Type / Q000096:biosynthesis / Q000737:chemistry*; D008077:Lipoproteins, LDL / Q000096:biosynthesis / Q000737:chemistry*; D008239:Lysine / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D017510:Protein Folding; D017459:Receptors, Amino Acid / Q000737:chemistry; D013552:Swine; D013816:Thermodynamics
chemical_list: D001054:Apolipoproteins A; D037181:Lectins, C-Type; D008077:Lipoproteins, LDL; D017459:Receptors, Amino Acid; C048648:tetranectin; D008239:Lysine