title: Solution structure of human apolipoprotein(a) kringle IV type 6.
abstract: The structure of apo(a) KIVT6 was investigated by two- and three-dimensional homo- and heteronuclear NMR spectroscopy. The solution structure of apo(a) KIVT6 contains only a small amount of regular secondary structure elements, comprising a short piece of antiparallel beta-sheet formed by residues Trp62-Tyr64 and Trp72-Tyr74, a short piece of parallel beta-sheet formed by the residues Cys1-Tyr2 and Thr78-Gln79, and a small 3(10)-helix within residues Thr38-Tyr40. The backbone as well as the side chains are arranged in a way similar to those of apo(a) KIVT7, apo(a) KIVT10, and plasminogen K4. We determined additionally the K(d) value of 0.31 +/- 0.04 mM for the binding of epsilon-aminocaproic acid (EACA) to apo(a) KIVT6 and mapped the binding region on apo(a) KIVT6 by means of chemical shift perturbation. This lysine binding activity, which was reported to occur within apo(a) KIVT5-8, is functionally different from the lysine binding activity found for apo(a) KIVT10.
authors.affiliation: Institute of Chemistry, Karl Franzens University Graz, Heinrichstrasse 28, A-8010 Graz, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Maderegger
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bermel
authors.forename: Andelko
authors.initials: A
authors.lastname: Hrzenjak
authors.forename: Gert M
authors.initials: GM
authors.lastname: Kostner
authors.forename: Heinz
authors.initials: H
authors.lastname: Sterk
mesh_terms: D001053:Apolipoproteins / Q000737:chemistry*; D053241:Apoprotein(a); D001665:Binding Sites; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D018082:Kringles; D017270:Lipoprotein(a) / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D001053:Apolipoproteins; D017270:Lipoprotein(a); D011994:Recombinant Proteins; D053241:Apoprotein(a); D003545:Cysteine