Complete assignment of the aromatic proton magnetic resonance spectrum of the kringle 1 domain from human plasminogen: structure of the ligand-binding site

Journal Article · Tue Jun 30 00:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00387a014· OSTI ID:5994708

Motta, A; Laursen, R A; Llinas, M; Tulinsky, A; Park, C H

The kringle 1 domain of human plasminogen has been investigated by /sup 1/H NMR spectroscopy at 300 and 600 MHz on the basis of a fragment obtained via controlled proteolysis of the zymogen with staphylococcus aureus V8 protease. The aromatic spectrum has been fully analyzed and all resonances assigned. The Tyr ring signals were identified by reference to the recently reported spectra of the plasminogen kringle 4 homologues from human, bovine, and porcine origin. Ligand binding was investigated by monitoring the effects of the antifibrinolytic drugs epsilon-aminohexanoic acid and p-benzylaminesulfonic acid (BASA) on the /sup 1/H NMR spectrum of kringle 1. Proton Overhauser experiments centered on aromatic transitions from these residues reveal efficient cross-relaxation with BASA, which indicates direct contacts between the hydrophobic side chain rings and the ligand hydrocarbon moiety at the binding site. Excellent overall agreement is found between the NMR data and the molecular folding of the prothrombin kringle I determined crystallographically. A structure is proposed here for the kringle 1 lysine-binding site which is based upon the NMR results, the x-ray structure, and computer graphics modeling. It is concluded that although features of the lysine-binding site are common to plasminogen kringles 1 and 4, in kringle 1 the binding site extends beyond the kringle inner loop as it encompasses residues Arg/sup 34/ and Phe/sup 36/ as well. Furthermore, it appears that in kringle 1 Arg/sup 34/ and Asp/sup 55/ are likely to play a direct role in the ligand-kringle 1 interaction by reinforcing the polarity of the cationic and anionic centers of the side chains of Arg/sup 71/ and Asp/sup 57/, which have been implicated to provide the electrostatic charges in kringle 4 that balance those of the ligand dipole at the binding site.

• Research Organization: Carnegie-Mellon Univ., Pittsburgh, PA
• OSTI ID: 5994708
• Journal Information: Biochemistry; (United States), Vol. 26:13
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
PLASMINOGEN
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
X-RAY DIFFRACTION
LIGANDS
MAN
PROTONS
STAPHYLOCOCCUS
STEREOCHEMISTRY
TRYPTOPHAN
TYROSINE
AMINO ACIDS
ANIMALS
AROMATICS
AZAARENES
AZOLES
BACTERIA
BARYONS
CARBOXYLIC ACIDS
COHERENT SCATTERING
DIFFRACTION
DRUGS
ELEMENTARY PARTICLES
FERMIONS
FIBRINOLYTIC AGENTS
HADRONS
HEMATOLOGIC AGENTS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROXY ACIDS
INDOLES
MAGNETIC RESONANCE
MAMMALS
MICROORGANISMS
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PRIMATES
PYRROLES
RESONANCE
SCATTERING
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550602 - Medicine- External Radiation in Diagnostics- (1980-)