Biomaterial Database

The conformational properties of human plasma apolipoprotein C-II. A spectroscopic study. 1980

W W Mantulin, and M F Rohde, and A M Gotto, and H J Pownall

The solution properties of human plasma apolipoprotein C-II (apoC-II) have been studied by analytical ultracentrifugation, circular dichroic spectroscopy, and fluorescence spectroscopy. ApoC-II self-associates in solution, even though no rigorous thermodynamic analysis of the mode of self-association could be established. The reversible denaturation of apoC-II by guanidinium chloride (GdmCl) proceeded in a sequential fashion. Initial disruption of protein self-association by 0.3 M GdmCl was followed by cooperative unfolding of monomeric protein at higher GdmCl concentratioans with a midpoint 1.1 M GdmCl. Based on tryptophan fluorescence quenching unfolded apoC-II was more permeable to penetration by small molecules than the self-associated protein. a very low free energy (delta GH2O = 2.8 kcal/mol) of denaturation was calculated from the GdmCl denaturation titration curve. Heating of apoC-II to 55 degrees C did not induce a reversible cooperative unfolding of the protein. Calculations, bsed on Chou-Fasman probability algorithms, reveal three sequential helical regions in apoC-II and one beta sheet structure (residues 61-74P. The locations of these regions are consistent with the known physiological functions of apoC-II.

UI	MeSH Term	Description	Entries
D006951	Hyperlipoproteinemias	Conditions with abnormally elevated levels of LIPOPROTEINS in the blood. They may be inherited, acquired, primary, or secondary. Hyperlipoproteinemias are classified according to the pattern of lipoproteins on electrophoresis or ultracentrifugation.	Hyperlipoproteinemia
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
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
D011489	Protein Denaturation	Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.	Denaturation, Protein,Denaturations, Protein,Protein Denaturations
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D006146	Guanidines	A family of iminourea derivatives. The parent compound has been isolated from mushrooms, corn germ, rice hulls, mussels, earthworms, and turnip juice. Derivatives may have antiviral and antifungal properties.
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D001053	Apolipoproteins	Protein components on the surface of LIPOPROTEINS. They form a layer surrounding the hydrophobic lipid core. There are several classes of apolipoproteins with each playing a different role in lipid transport and LIPID METABOLISM. These proteins are synthesized mainly in the LIVER and the INTESTINES.	Apolipoprotein
D001056	Apolipoproteins C	A group of apolipoproteins that can readily exchange among the various classes of lipoproteins (HDL; VLDL; CHYLOMICRONS). After lipolysis of TRIGLYCERIDES on VLDL and chylomicrons, Apo-C proteins are normally transferred to HDL. The subtypes can modulate remnant binding to receptors, LECITHIN CHOLESTEROL ACYLTRANSFERASE, or LIPOPROTEIN LIPASE.	Apo-C,Apo C,ApoC,Apoprotein (C),Apoproteins C