Structural basis for the conformational adaptability of apolipophorin III, a helix-bundle exchangeable apolipoproteinWang, J., Sykes, B.D., Ryan, R.O.
(2002) Proc.Natl.Acad.Sci.USA 99: 1188-1193
- PubMed: 11818551
- DOI: 10.1073/pnas.032565999
- PubMed Abstract:
- Insight into Lipid Surface Recognition and Reversible Conformational Adaptation of an Exchangeable Apolipoprotein by Multidimensional Heteronuclear NMR Techniques
Wang, J.,Gagne, S.M.,Sykes, B.D.,Ryan, R.O.
(1997) J.Biol.Chem. 272: 17912
The high-resolution NMR structure of apolipophorin III from the sphinx moth, Manduca sexta, has been determined in the lipid-free state. We show that lipid-free apolipophorin III adopts a unique helix-bundle topology that has several characteristic s ...
The high-resolution NMR structure of apolipophorin III from the sphinx moth, Manduca sexta, has been determined in the lipid-free state. We show that lipid-free apolipophorin III adopts a unique helix-bundle topology that has several characteristic structural features. These include a marginally stable, up-and-down helix bundle that allows for concerted opening of the bundle about "hinged" loops upon lipid interaction and buried polar/ionizable residues and buried interhelical H-bonds located in the otherwise hydrophobic interior of the bundle that adjust protein stability and facilitate lipid-induced conformational opening. We suggest that these structural features modulate the conformational adaptability of the lipid-free helix bundle upon lipid binding and control return of the open conformation to the original lipid-free helix-bundle state. Taken together, these data provide a structural rationale for the ability of exchangeable apolipoproteins to reversibly interact with circulating lipoprotein particles.
Department of Biochemistry and Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, IL 62901-4413, USA. email@example.com