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Hapten conformation in the combining site of antibodies that bind phenylphosphocholine.
- Source :
-
Biochemistry [Biochemistry] 1992 Jan 21; Vol. 31 (2), pp. 584-9. - Publication Year :
- 1992
-
Abstract
- We have shown previously that anti-phenylphosphocholine antibodies elicited by phosphocholine-keyhole limpet hemocyanin can be divided into two populations according to their ability to recognize the two hapten analogues p-nitrophenylphosphocholine (NPPC) and p-nitrophenyl 3,3-dimethylbutyl phosphate (NPDBP). These analogues differ from each other in that NPPC has a positively charged nitrogen in the choline moiety, whereas NPDBP lacks the positively charged nitrogen. Group II-A antibodies bind only NPPC, whereas group II-B antibodies bind both ligands. Here, by infrared and nuclear magnetic resonance spectroscopic investigations, we find that when free in solution NPPC has a predominantly fixed structure in which the termini approach each other, probably due to electrostatic interactions within the molecule; this "bent" structural feature is retained when the ligand is bound by antibody. In contrast, the structure of unbound NPDBP is less fixed, being characterized by rapidly interchanging conformations corresponding to an open chain structure with less overall proximity of the termini compared to NPPC. The overall shape of NPPC is essentially unaltered by binding, whereas in the case of NPDBP what was a minor conformation in the unbound state becomes the predominate conformation of the bound ligand. Thus, our results are consistent with these antibodies providing a molecular template for stabilizing the conformation of the bound ligand.
- Subjects :
- Haptens immunology
Magnetic Resonance Spectroscopy
Nitrophenols immunology
Phosphorylcholine chemistry
Phosphorylcholine immunology
Protein Conformation
Spectrophotometry, Infrared
Antibodies, Monoclonal chemistry
Binding Sites, Antibody
Haptens chemistry
Nitrophenols chemistry
Phosphorylcholine analogs & derivatives
Subjects
Details
- Language :
- English
- ISSN :
- 0006-2960
- Volume :
- 31
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 1731913
- Full Text :
- https://doi.org/10.1021/bi00117a040