1EQ1: NMR STRUCTURE OF AN EXCHANGEABLE APOLIPOPROTEIN-MANDUCA SEXTA APOLIPOPHORIN-III

Citation:
Abstract
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.
PDB ID: 1EQ1Download
MMDB ID: 18635
PDB Deposition Date: 2000/3/31
Updated in MMDB: 2007/11
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Molecular Components in 1EQ1
Label Count Molecule
Protein (1 molecule)
1
Apolipophorin-iii
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB
.