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The solution structure of kringle 4
Author(s) -
Trexler M.,
Bányai L.,
Patthy L.,
Pluck N.D.,
Williams R.J.P.
Publication year - 1983
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(83)80173-2
Subject(s) - chemistry , stereochemistry , kringle domain , titration , nuclear magnetic resonance spectroscopy , binding site , residue (chemistry) , metal ions in aqueous solution , ion , organic chemistry , biochemistry , plasmin , enzyme
Kringle 4 of human plasminogen has been studied by NMR spectroscopy to define the solution structure of the kringle‐fold and to characterize the ω‐aminocarboxylic acid binding site. Aromatic and aliphatic resonances of the NMR spectrum have been identified with the aid of spin‐decoupling and NOE procedures as well as pH‐titration and metal ion probe studies. Comparison of the NMR spectrum of kringle 4 with the spectra of various kringle 4 species chemically modified at defined positions permitted the assignment of several resonances to specific residues in the kringle 4 sequence. The NOE studies revealed that Leu 45 is in close proximity of the sequentially distant Trp 25 /Trp 61 residue pair, thus delineating a definite structural feature of the kringle‐fold. The binding of 6‐aminohexanoic acid to kringle 4 was shown to cause shifts in the resonances of several aromatic residues, including those of Trp 71 , suggesting that several aromatic residues may be lining the ω‐aminocarboxylic acid binding site. The binding of the ligand is competitive with the binding of lanthanide ions which reveal much detail of this site.