A proximal pair of positive charges provides the dominant ligand-binding contribution to complement-like domains from the LRP (low-density lipoprotein receptor-related protein)
| Autor: | Klavs Dolmer, Peter G.W. Gettins |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Models
Molecular Lysine Amino Acid Motifs 2-ME 2-mercaptoethanol Biochemistry 0302 clinical medicine Protein structure low-density lipoprotein receptor-related protein (LRP) GST glutathione transferase complement-like repeat domain (CR domain) 0303 health sciences Alanine Chemistry ligand specificity uPA urokinase-type plasminogen activator Hydrogen-Ion Concentration Ligand (biochemistry) RP-HPLC reverse-phase HPLC Recombinant Proteins low-density lipoprotein receptor LPL lipoprotein lipase PAI-1 plasminogen activator inhibitor-1 030220 oncology & carcinogenesis LDLR low-density lipoprotein receptor Research Article α2M α2-macroglobulin model compound Arginine RAP receptor-associated protein TEV tobacco etch virus 03 medical and health sciences thermodynamics Humans Histidine Binding site CR complement-like repeat Molecular Biology Binding selectivity LDL-Receptor Related Proteins 030304 developmental biology Aspartic Acid Binding Sites lysine binding Cell Biology Peptide Fragments Protein Structure Tertiary VLDLR very-low-density lipoprotein receptor Spectrometry Fluorescence LDL receptor IPTG isopropyl β-D-thiogalactoside affinity LRP low-density lipoprotein receptor-related protein Protein ligand |
| Zdroj: | Biochemical Journal |
| ISSN: | 1470-8728 |
| Popis: | The LRP (low-density lipoprotein receptor-related protein) can bind a wide range of structurally diverse ligands to regions composed of clusters of ~40 residue Ca2+-dependent, disulfide-rich, CRs (complement-like repeats). Whereas lysine residues from the ligands have been implicated in binding, there has been no quantification of the energetic contributions of such interactions and hence of their relative importance in overall affinity, or of the ability of arginine or histidine residues to bind. We have used four representative CR domains from the principal ligand-binding cluster of LRP to determine the energetics of interaction with well-defined small ligands that include methyl esters of lysine, arginine, histidine and aspartate, as well as N-terminally blocked lysine methyl ester. We found that not only lysine but also arginine and histidine bound well, and when present with an additional proximal positive charge, accounted for about half of the total binding energy of a protein ligand such as PAI-1 (plasminogen activator inhibitor-1). Two such sets of interactions, one to each of two CR domains could thus account for almost all of the necessary binding energy of a real ligand such as PAI-1. For the CR domains, a central aspartate residue in the sequence DxDxD tightens the Kd by ~20-fold, whereas DxDDD is no more effective. Together these findings establish the rules for determining the binding specificity of protein ligands to LRP and to other LDLR (low-density lipoprotein receptor) family members. |
| Databáze: | OpenAIRE |
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