1O72: Crystal Structure Of The Water-soluble State Of The Pore-forming Cytolysin Sticholysin Ii Complexed With Phosphorylcholine

Sticholysin II (StnII) is a pore-forming protein (PFP) produced by the sea anemone Stichodactyla helianthus. We found out that StnII exists in a monomeric soluble state but forms tetramers in the presence of a lipidic interface. Both structures have been independently determined at 1.7 A and 18 A resolution, respectively, by using X-ray crystallography and electron microscopy of two-dimensional crystals. Besides, the structure of soluble StnII complexed with phosphocholine, determined at 2.4 A resolution, reveals a phospholipid headgroup binding site, which is located in a region with an unusually high abundance of aromatic residues. Fitting of the atomic model into the electron microscopy density envelope suggests that while the beta sandwich structure of the protein remains intact upon oligomerization, the N-terminal region and a flexible and highly basic loop undergo significant conformational changes. These results provide the structural basis for the membrane recognition step of actinoporins and unexpected insights into the oligomerization step.
PDB ID: 1O72Download
MMDB ID: 25277
PDB Deposition Date: 2002/10/23
Updated in MMDB: 2003/12
Experimental Method:
x-ray diffraction
Resolution: 2.41  Å
Source Organism:
Similar Structures:
Biological Unit for 1O72: monomeric; determined by author and by software (PQS)
Molecular Components in 1O72
Label Count Molecule
Protein (1 molecule)
Sticholysin II
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

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