1s8i

Crystal structure of Lys49-Phospholipase A2 from Agkistrodon contortrix laticinctus, second fatty acid free form

spinqualitylabelsall models 1s8i, resolution 1.61Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1s8i is a 1 chain structure with sequence from Agkistrodon contortrix laticinctus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SO4 Related: 1s8g, 1s8h Activity: Phospholipase A(2), with EC number 3.1.1.4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [PA2H1_AGKCL] Snake venom phospholipase A2 homolog that has myotoxic activities. Lacks enzymatic activity. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Agkistrodon contortrix laticinctus myotoxin is a Lys(49)-phospholipase A(2) (EC 3.1.1.4) isolated from the venom of the serpent A. contortrix laticinctus (broad-banded copperhead). We present here three monomeric crystal structures of the myotoxin, obtained under different crystallization conditions. The three forms present notable structural differences and reveal that the presence of a ligand in the active site (naturally presumed to be a fatty acid) induces the exposure of a hydrophobic surface (the hydrophobic knuckle) toward the C terminus. The knuckle in A. contortrix laticinctus myotoxin involves the side chains of Phe(121) and Phe(124) and is a consequence of the formation of a canonical structure for the main chain within the region of residues 118-125. Comparison with other Lys(49)-phospholipase A(2) myotoxins shows that although the knuckle is a generic structural motif common to all members of the family, it is not readily recognizable by simple sequence analyses. An activation mechanism is proposed that relates fatty acid retention at the active site to conformational changes within the C-terminal region, a part of the molecule that has long been associated with Ca(2+)-independent membrane damaging activity and myotoxicity. This provides, for the first time, a direct structural connection between the phospholipase "active site" and the C-terminal "myotoxic site," justifying the otherwise enigmatic conservation of the residues of the former in supposedly catalytically inactive molecules. A molecular mechanism for Lys49-phospholipase A2 activity based on ligand-induced conformational change.,Ambrosio AL, Nonato MC, de Araujo HS, Arni R, Ward RJ, Ownby CL, de Souza DH, Garratt RC J Biol Chem. 2005 Feb 25;280(8):7326-35. Epub 2004 Dec 13. PMID:15596433 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phospholipase A2 3D structures

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