4NT1: Crystal Structure Of Apo-form Of Arabidopsis Acd11 (accelerated-cell- Death 11) At 1.8 Angstrom Resolution

Citation:
Abstract
The accelerated cell death 11 (acd11) mutant of Arabidopsis provides a genetic model for studying immune response activation and localized cellular suicide that halt pathogen spread during infection in plants. Here, we elucidate ACD11 structure and function and show that acd11 disruption dramatically alters the in vivo balance of sphingolipid mediators that regulate eukaryotic-programmed cell death. In acd11 mutants, normally low ceramide-1-phosphate (C1P) levels become elevated, but the relatively abundant cell death inducer phytoceramide rises acutely. ACD11 exhibits selective intermembrane transfer of C1P and phyto-C1P. Crystal structures establish C1P binding via a surface-localized, phosphate headgroup recognition center connected to an interior hydrophobic pocket that adaptively ensheaths lipid chains via a cleft-like gating mechanism. Point mutation mapping confirms functional involvement of binding site residues. A pi helix (pi bulge) near the lipid binding cleft distinguishes apo-ACD11 from other GLTP folds. The global two-layer, alpha-helically dominated, "sandwich" topology displaying C1P-selective binding identifies ACD11 as the plant prototype of a GLTP fold subfamily.
PDB ID: 4NT1Download
MMDB ID: 117318
PDB Deposition Date: 2013/11/29
Updated in MMDB: 2014/02
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 4NT1: monomeric; determined by author and by software (PISA)
Molecular Components in 4NT1
Label Count Molecule
Protein (1 molecule)
1
Accelerated-cell-death 11(Gene symbol: ACD11)
Molecule annotation
Chemical (1 molecule)
1
1
* Click molecule labels to explore molecular sequence information.

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