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Direct measurement of the interactions of glycosaminoglycans and a heparin decasaccharide with the malaria circumsporozoite protein.

Authors :
Rathore D
McCutchan TF
Garboczi DN
Toida T
Hernáiz MJ
LeBrun LA
Lang SC
Linhardt RJ
Source :
Biochemistry [Biochemistry] 2001 Sep 25; Vol. 40 (38), pp. 11518-24.
Publication Year :
2001

Abstract

Circumsporozoite (CS) protein is a predominant surface antigen of malaria sporozoites, the infective form of the parasite, and has been used for making anti-malaria vaccines. For the first time we have examined the interaction of CS protein with various glycosaminoglycans in real time using surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). Heparin was the best binder among the glycosaminoglycans tested and bound to CS protein with nanomolar affinity. Using purified and structurally defined small heparin oligosaccharides, we identified a decasaccharide to be the minimum sized CS protein-binding sequence. In an indirect competition assay, this decasaccharide blocked the CS protein interaction with HepG2 cells with an ID(50) of less than 60 nM. The decasaccharide has a structure commonly found in hepatic heparan sulfate, and the same sequence has recently been shown to bind specifically to apolipoprotein E. Examination of porcine liver heparan sulfate in this indirect competition assay showed that it and heparin were the only glycosaminoglycans that could effectively block CS protein interaction with HepG2 cells in culture. These data support the hypothesis that the invasion of liver cells by the parasite shares a common mechanism with the hepatic uptake of lipoprotein remnants from the blood.

Details

Language :
English
ISSN :
0006-2960
Volume :
40
Issue :
38
Database :
MEDLINE
Journal :
Biochemistry
Publication Type :
Academic Journal
Accession number :
11560500
Full Text :
https://doi.org/10.1021/bi0105476