Structural basis for the conformational adaptability of apolipophorin III, a helix-bundle exchangeable apolipoprotein
AUTOR(ES)
Wang, Jianjun
FONTE
The National Academy of Sciences
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=122165Documentos Relacionados
- A molecular trigger of lipid binding-induced opening of a helix bundle exchangeable apolipoprotein
- Structural basis for receptor binding heterogeneity of apolipoprotein E from type III hyperlipoproteinemic subjects.
- The helix-hairpin-helix DNA-binding motif: a structural basis for non-sequence-specific recognition of DNA.
- Structural basis for PAS domain heterodimerization in the basic helix–loop–helix-PAS transcription factor hypoxia-inducible factor
- Transmembrane four-helix bundle of influenza A M2 protein channel: structural implications from helix tilt and orientation.