Biomaterial Database

Structural differences in the two calcium binding sites of the porcine intestinal calcium binding protein: a multinuclear NMR study. 1985

H J Vogel, and T Drakenberg, and S Forsén, and J D O'Neil, and T Hofmann

Cadmium-113 and calcium-43 NMR spectra of Cd2+ and Ca2+ bound to the porcine intestinal calcium binding protein (ICaBP; Mr 9000) contain two resonances. The first resonance is characterized by NMR parameters resembling those found for these cations bound to proteins containing the typical helix-loop-helix calcium binding domains of parvalbumin, calmodulin, and troponin C, which are defined as EF-hands by Kretsinger [Kretsinger, R. H. (1976) Annu. Rev. Biochem. 45, 239]. The second resonance in both spectra has a unique chemical shift and is consequently assigned to the metal ion bound in the N-terminal site of ICaBP. This site is characterized by an insertion of a proline in the loop of the helix-loop-helix domain and will be called the pseudo-EF-hand site. The binding of Cd2+ to the apo form of ICaBP is sequential. The EF-hand site is filled first. Both binding sites have similar, but not identical, affinities for Ca2+: at a Ca2+ to protein ratio of 1:1, 65% of the ion is bound in the EF-hand site and 35% in the pseudo-EF-hand site. The two sites do not appear to act independently; thus, replacement of Ca2+ or Cd2+ by La3+ in the EF-hand site causes changes in the environment of the ions in the pseudo-EF-hand site. In addition, the chemical shift of Cd2+ bound to the EF-hand site is dependent on the presence or absence of Ca2+ or Cd2+ in the pseudo-EF-hand site.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007082	Ileum	The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
D007413	Intestinal Mucosa	Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.	Intestinal Epithelium,Intestinal Glands,Epithelium, Intestinal,Gland, Intestinal,Glands, Intestinal,Intestinal Gland,Mucosa, Intestinal
D009682	Magnetic Resonance Spectroscopy	Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).	In Vivo NMR Spectroscopy,MR Spectroscopy,Magnetic Resonance,NMR Spectroscopy,NMR Spectroscopy, In Vivo,Nuclear Magnetic Resonance,Spectroscopy, Magnetic Resonance,Spectroscopy, NMR,Spectroscopy, Nuclear Magnetic Resonance,Magnetic Resonance Spectroscopies,Magnetic Resonance, Nuclear,NMR Spectroscopies,Resonance Spectroscopy, Magnetic,Resonance, Magnetic,Resonance, Nuclear Magnetic,Spectroscopies, NMR,Spectroscopy, MR
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002135	Calcium-Binding Proteins	Proteins to which calcium ions are bound. They can act as transport proteins, regulator proteins, or activator proteins. They typically contain EF HAND MOTIFS.	Calcium Binding Protein,Calcium-Binding Protein,Calcium Binding Proteins,Binding Protein, Calcium,Binding Proteins, Calcium,Protein, Calcium Binding,Protein, Calcium-Binding
D002413	Cations, Divalent	Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis.	Divalent Cations
D004386	Duodenum	The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.	Duodenums
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia