4a2y

STRUCTURE OF THE HUMAN EOSINOPHIL CATIONIC PROTEIN IN COMPLEX WITH CITRATE ANIONS

spinqualitylabelsall models 4a2y, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4a2y is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.7Å Ligands: CIT, MPD Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ECP_HUMAN Cytotoxin and helminthotoxin with low-efficiency ribonuclease activity. Possesses a wide variety of biological activities. Exhibits antibacterial activity, including cytoplasmic membrane depolarization of preferentially Gram-negative, but also Gram-positive strains. Promotes E.coli outer membrane detachment, alteration of the overall cell shape and partial loss of cell content. Publication Abstract from PubMed The human eosinophil cationic protein (ECP), also known as RNase 3, is an eosinophil secretion protein that is involved in innate immunity and displays antipathogen and proinflammatory activities. ECP has a high binding affinity for heterosaccharides, such as bacterial lipopolysaccharides and heparan sulfate found in the glycocalix of eukaryotic cells. We have crystallized ECP in complex with sulfate anions in a new monoclinic crystal form. In this form, the active site groove is exposed, providing an alternative model for ligand binding studies. By exploring the protein-sulfate complex, we have defined the sulfate binding site architecture. Three main sites (S1-S3) are located in the protein active site; S1 and S2 overlap with the phosphate binding sites involved in RNase nucleotide recognition. A new site (S3) that is unique to ECP is one of the key anchoring points for sulfated ligands. Arg 1 and Arg 7 in S3, together with Arg 34 and Arg 36 in S1, form the main basic clusters that assist in the recognition of ligand anionic groups. The location of additional sulfate bound molecules, some of which contribute to the crystal packing, may mimic the binding to extended anionic polymers. In conclusion, the structural data define a binding pattern for the recognition of sulfated molecules that can modulate the role of ECP in innate immunity. The results reveal the structural basis for the high affinity of ECP for glycosaminoglycans and can assist in structure-based drug design of inhibitors of the protein cytotoxicity to host tissues during inflammation. The sulfate-binding site structure of the human eosinophil cationic protein as revealed by a new crystal form.,Boix E, Pulido D, Moussaoui M, Victoria Nogues M, Russi S J Struct Biol. 2012 Jul;179(1):1-9. Epub 2012 May 9. PMID:22579681 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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