Related Experiment Video
Updated: Jul 19, 2026

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
A metal ion-binding site in the kringle region of bovine prothrombin fragment 1
P Berkowitz1, N W Huh, K E Brostrom
1Department of Chemistry, University of North Carolina, Chapel Hill 27599-3290.
Abstract:
45Ca(II) binding studies (equilibrium dialysis) on the kringle domain of bovine prothrombin fragment 1 were conducted using a mixture of peptides (residues 43-156 and 46-156) resulting from limited alpha-chymotryptic hydrolysis of fragment 1. Analysis of the Scatchard plot of these data indicates a single, low affinity Ca(II)-binding site to be present. Similar results were obtained from studies on the decarboxylated fragment 1 derivative, 10-gamma-MGlu-fragment 1. Acetylation of bovine fragment 1 in the absence of Ca(II) or Mg(II) ions results in the loss of the metal ion-promoted quenching of the intrinsic Trp fluorescence of the protein and the Ca(II)-mediated binding to phosphatidylserine/phosphatidylcholine (PS/PC) vesicles. The acetylation of the NH2 alpha-group of Ala-1 has been shown (Welsch, D. J., and Nelsestuen, G. L. (1988) Biochemistry 27, 4946-4952) to abolish the PS/PC binding property of fragment 1. The present study demonstrates that acetylation of a second site possibly Ser-79 or Thr-81 using the conditions described in the preceding paper results in loss of both the fluorescence transition and the Ca(II)-mediated PS/PC binding of the resulting protein derivative. Removal of the O-acetyl group at the Ser-79/Thr-81 site is accomplished by aminolysis with 0.2 M hydroxylamine, pH 10, 50 degrees C; the fluorescence transition is partially restored. PS/PC binding is partially restored if the NH2 alpha-group of Ala-1 is trinitrophenylated but is not restored if the NH2 alpha-group of Ala-1 is acetylated. We conclude that the Ser-79/Thr-81 site may represent a portion of the metal ion-binding site within the kringle domain of fragment 1. Occupancy of this site by a Ca(II) ion appears to be important in the binding of the protein to PS/PC vesicles.
More Related Videos
08:26Luminophore Formation in Various Conformations of Bovine Serum Albumin by Binding of Gold(III)
Published on: August 31, 2018
07:22The Development and Application of Biophysical Assays for Evaluating Ternary Complex Formation Induced by Proteolysis Targeting Chimeras (PROTACS)
Published on: January 12, 2024
Related Concept Videos
Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
Valence Bond Theory
Ligand Binding Sites
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Conserved Binding Sites
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...
Ligand Binding and Linkage
EDTA: Conditional Formation Constant
For the equilibrium reaction of the metal with the Y4− form of EDTA, the formation...