Title : Structure of human
apolipoprotein D : locations of the intermolecular and intramolecular disulfide links
Abstract :
- We have determined the primary structure of human apolipoprotein D ( apoD ) by aligning peptides derived from digestions by cyanogen bromide, trypsin, and chymotrypsin
- Our results confirm the primary structure derived from cDNA [Drayna et al. (1986) J. Biol
- Chem
- 261, 16535-16539]
- ApoD consists of 169 amino acid residues , including 5 cysteines
- Tryptic peptide analysis indicated that Cys41 and Cys16 are joined by a disulfide bridge
- Using a combination of manual Edman degradations and mass spectrometric analysis on a purified cluster of chymotryptic fragments , we identified an intramolecular disulfide bridge between Cys8 and Cys114 and an intermolecular bridge between Cys116 of apoD and Cys6 of apoA-II
- In addition, sites of N-glycosylation were found at Asn45 and Asn78
- Because apoD contains two intramolecular disulfide linkages and has a high content of proline to disrupt alpha-helical structures, formation of the amphipathic helical regions that characterize the other soluble apolipoproteins is unlikely
- We conclude that apoD binds to lipoprotein surfaces through structures other than alpha-helices, such as disulfide links
Output (sent_index, trigger,
protein,
sugar,
site):
- 8. N-glycosylation, , -, -, sites
Output(Part-Of) (sent_index,
protein,
site):
- 7. apoA-II, Cys6
- 7. apoD, Cys8 and Cys114
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):