Amino acid sequence apolipoprotein

B6. Brewer, H. B., Shulinan, R., Herbert, P., Ronan, R., and Wehrly, K., The complete amino acid sequence of an apolipoprotein obtained from human very low deirsity lipoprotein (VLDL). Admn. Exp. Med. Biol. 26, 280 (1972). 

The primary amino acid sequence of apoA-I has been published by Brewer and colleagues (B43) and, with a few minor differences, by Baker et al. (Bl). As with other apolipoproteins that have been sequenced, there are no long sequences of hydrophobic or hydrophilic amino acids, but there is evidence that amphipathic regions of a-helices are formed during combination with lipid, with one face of each helical region more hydrophobic than its opposite face (07). 

B43. Brewer, H. B., Jr., Fairwell, T., Larue, A., Ronan, R., Houser, A., and Bronzert, T., The amino acid sequence of human apoA-1, an apolipoprotein isolated from high density lipoproteins. Biochem. Biophys. Res. Common. 80, 623-630 (1978). 

M24. Malmendier, C. L., Delctoix, C., and Fontaine, M., Effect of sialic acid removal on human low density lipoprotein catabolism in vivo. Atherosclerosis 37, 277-284 (1980). M25. Malmendier, C. L., Paroutaud, P., and Ameryckx, J. P., Partial amino acid sequence of three new apolipoproteins isolated from human high density lipoproteins. FEBS Lett. 109, 43-44 (1980). 

Human phosphate binding protein (HPBP), an apolipoprotein that binds inorganic phosphate in blood, was serendipitously discovered. Its three-dimensional structure and complete amino acid sequence were solved (Morales et al, 2006 Diemer et al, 2008). The conditions found to separate HPBP and PONl in vitro indicated that HPBP is strongly associated with PONl (Renault et al, 2006). Moreover, the stabilization of the active form(s) of human PONl by HPBP suggests that HPBP could be a functional chaperone for PONl (Rochu et al, 2007b, c). 

RaU SC, Jr., Weisgraber KH, Mahley RW (1982) Human apolipoprotein E. The complete amino acid sequence. J Biol Chem 257 4171 178. 

Fig. 1. Comparison of amino acid sequences of apolipoprotein from 10 species. Sequences are aligned against human apoE4. Hu, Human (Rail et ai, 1982a) Ba, baboon (Hixson et

There is one molecule each of apoLp-I and apoLp-lI in each lipophorin molecule (Shapiro et al., 1984 Surholt et al., 1992). A similar amino acid composition, as well as the presence of oligosaccharide chains of the high-mannose type, has been observed for apoLp-I and apoLp-II from different insect species (Pattnaik et al., 1979 Ryan et al., 1984 Shapiro et al., 1984 Kashiwazaki and Ikai, 1985 Dillwith et al., 1986 Nagao and Chino, 1987 Rimoldi o/., 1991). Both apolipoproteins are water insoluble when separated from lipophorin, and in this regard resemble vertebrate apoB. No amino acid sequence data, either from direct or cDNA... 

Hospattankar AV, Fairwell T, Ronan R, Brewer HB Jr (1983) Amino acid sequences of human apolipoprotein C-II from normal and hyperlipoproteinemic subjects. J Biol Chem 259 318-322... 

Diemer, H., Elias, M., Renault R/ et al., 2008. Tandem use of X-ray crystallography and mass spectrometry to obtain ab initio the complete and exact amino acids sequence of HP BP, a human 38kDa apolipoprotein. Proteins Struct. 

Analysis of the amino acid sequence of plasma apolipoproteins led to the proposal (Segrest et al., 1974) that the apolipoprotein... 

A specific amino acid sequence of either apoA-I or apoC-I is not necessary for activation of LCAT by an apolipoprotein (Pownall... 

Using these methods, it has been demonstrated that apolar lipids associate at the hydrophobic surfaces of amphipathic a-helical regions of specific amino acid sequences of apolipoproteins while phospholipids and water interact at polar surfaces. Interaction of the major apolipoproteins of HDL with lipids stabilizes the a-helical structure and increases its content. In contrast, as the lipid content of LDL increases, the /3-structure of apoB increases. 

The carboxy-terminal region in apolipoprotein (a) closely resembles the protease domain in plasminogen [eight amino acid substitutions, nine amino acid deletions, and one insertion in apo(a) relative to plasminogen, with 94% overall nucleotide sequence identity] (G28). The most important difference is the substitution of arginine by serine in the site responsible for proteolytic activity (position 4308) (G28). As a result, Lp(a) has no protease activity towards substrates for plasmin (J3). Salonen (SI) reported a serine-protease activity of Lp(a) towards fibronectin, a glycoprotein present in connective tissue matrices. 

Apolipoprotein A-I is the primary protein component of HDL.23 2513 Most of the 243 residues consist of a nearly continuous amphipathic a helix with kinks at regularly spaced proline residues.26 28 Two disulfide-linked ApoA-I molecules may form a belt that encircles the discoid lipoprotein.2513 ApoA-II is the second major HDL protein, but no dearly specialized function has been identified.29 30 ApoA-I, II, and IV, apoC-I, II, and III, and apoE all have multiple repeats of 22 amino acids with sequences that suggest amphipathic helices. Tire 391-residue ApoA-IV has 13 tandem 22-residue repeats. Proline and glycine are present in intervening hinge regions.23 This may enable these proteins to spread over and penetrate the surfaces of the lipoprotein micelles. Most of these proteins are encoded by a related multigene family.7 303... 

Apolipoprotein C-I can be isolated from VLDL (B56, S52) or HDL (08) by repeated chromatography. It has been sequenced and found to contain 57 residues (J8, S33). It appears to be highly helical on lipid binding (J7), with three lipid-binding helical sequences predicted by Chou-Fasman analysis (S22). Both native and synthetic apoC-I bind lipid, and also activate LCAT (H7, S34, S46). This dual activity is probably due to the peptide which contains amino acids 17-57 this sequence appears to activate LCAT, and the sequence 32-57 appears to bind lipid (S49). ApoC-I readily selfassociates in aqueous solution (07). 

ApoSAA, normally a trace component of plasma, is an acute-phase plasma protein, that is, one that is elevated in a variety of disease states (R18). Its identification is interesting. A small protein of 76 residues, now called protein AA, was identified during the study of the proteins present in extracellular amyloid deposits in the type of amyloidosis particularly associated with inflammation (B24, H36, Lll, S38), Antibodies to protein AA reacted with two AA-related proteins in plasma, one of approximate Mr 180,000 (SAA) and the other found in HDL of Mr 14,000-15,000 or 12,000 (apoSAA) (A19, B25, B26, L12, L15). The N-terminal 76-amino-acid portion of apoSAA is identical to that of amyloid protein AA (E8). Human apoSAA has now been sequenced and has been shown to consist of 104 amino acid residues (B27). Further studies in man have demonstrated microheterogeneity in apoSAA (B18, B19, M30) and Benditt et al. describe specific amino acid substitutions (B27, P6). Shore et al. have described a second similar threonine-poor apolipoprotein, apparently a dimer of Mr 40,000... 

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