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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
35
pubmed:dateCreated
2002-8-30
pubmed:abstractText
An initial event in atherosclerosis is the retention of lipoproteins within the intima of the vessel wall. Previously we identified Site B (residues 3359-3369) in apolipoprotein (apo) B100 as the proteoglycan binding sequence in low density lipoproteins (LDLs) and showed that the atherogenicity of apoB-containing lipoproteins is linked to their affinity for artery wall proteoglycans. However, both apoB100- and apoB48-containing lipoproteins are equally atherogenic even though Site B lies in the carboxyl-terminal half of apoB100 and is absent in apoB48. If binding to proteoglycans is a key step in atherogenesis, apoB48-containing lipoproteins must bind to proteoglycans via other proteoglycan binding sites in the amino-terminal 48% of apoB. In vitro studies have identified five clusters of basic amino acids in delipidated apoB48 that bind negatively charged glycosaminoglycans. To determine which of these sites is functional on LDL particles, we analyzed the proteoglycan binding activity of recombinant human LDLs from transgenic mice or rat hepatoma cells. Substitution of neutral amino acids for the basic amino acids in Site B-Ib (residues 84-94) abolished the proteoglycan binding activity of recombinant apoB53. Carboxyl-truncated apoB80 bound biglycan with higher affinity than apoB100 and apoB48. ApoB80 in which Site B was mutated had the same affinity for proteoglycans as apoB48. These data support the hypothesis that the carboxyl terminus of apoB100 "masks" Site B-Ib, the amino-terminal proteoglycan binding site, and that this site is exposed in carboxyl-truncated forms of apoB. The presence of a proteoglycan binding site in the amino-terminal region of apoB may explain why apoB48- and apoB100-containing lipoproteins are equally atherogenic.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
32228-33
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:12070165-Amino Acid Sequence, pubmed-meshheading:12070165-Amino Acid Substitution, pubmed-meshheading:12070165-Animals, pubmed-meshheading:12070165-Apolipoprotein B-48, pubmed-meshheading:12070165-Apolipoproteins B, pubmed-meshheading:12070165-Arteriosclerosis, pubmed-meshheading:12070165-Binding Sites, pubmed-meshheading:12070165-Cell Line, pubmed-meshheading:12070165-Glycosaminoglycans, pubmed-meshheading:12070165-Heparin, pubmed-meshheading:12070165-Humans, pubmed-meshheading:12070165-Kinetics, pubmed-meshheading:12070165-Mice, pubmed-meshheading:12070165-Mice, Transgenic, pubmed-meshheading:12070165-Models, Molecular, pubmed-meshheading:12070165-Mutagenesis, Site-Directed, pubmed-meshheading:12070165-Protein Conformation, pubmed-meshheading:12070165-Proteoglycans, pubmed-meshheading:12070165-Recombinant Proteins, pubmed-meshheading:12070165-Restriction Mapping, pubmed-meshheading:12070165-Transfection
pubmed:year
2002
pubmed:articleTitle
Identification of the proteoglycan binding site in apolipoprotein B48.
pubmed:affiliation
Wallenberg Laboratory for Cardiovascular Research, The Sahlgrenska Academy at Göteborg University, S-413 45 Göteborg, Sweden.
pubmed:publicationType
Journal Article