1ica

REFINED THREE-DIMENSIONAL STRUCTURE OF INSECT DEFENSIN A

spinqualitylabelsall models 1ica Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ica is a 1 chain structure with sequence from Protophormia terraenovae. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR, 10 models Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DEFI_PROTE Responsible for the anti Gram-positive activity of immune hemolymph of P.terraenovae. 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 BACKGROUND: Insect defensin A is a basic 4 kDa protein secreted by Phormia terranovae larvae in response to bacterial challenges or injuries. Previous biological tests suggest that the bacterial cytoplasmic membrane is the target of defensin A. The structural study of this protein is the first step towards establishing a structure-activity relationship and forms the basis for understanding its antibiotic activity at the molecular level. RESULTS: We describe a refined model of the three-dimensional structure of defensin A derived from an extensive analysis of 786 inter-proton nuclear Overhauser effects. The backbone fold involves an N-terminal loop and an alpha-helical fragment followed by an antiparallel beta-structure. The helix and the beta-structure are connected by two of the three disulphide bridges present in defensin A, forming a so-called 'cysteine-stabilized alpha beta' (CS alpha beta) motif. The N-terminal loop, which is locally well defined, can occupy different positions with respect to the other moieties of the molecule. CONCLUSIONS: The CS alpha beta motif, which forms the core of the defensin A structure, appears to be a common organization for several families of small proteins with toxic properties. The distribution of amino acid side chains in the protein structure creates several hydrophobic or hydrophilic patches. This leads us to propose that the initial step in the action of positively charged defensin A molecules with cytoplasmic membranes may involve interactions with acidic phospholipids. Refined three-dimensional solution structure of insect defensin A.,Cornet B, Bonmatin JM, Hetru C, Hoffmann JA, Ptak M, Vovelle F Structure. 1995 May 15;3(5):435-48. PMID:7663941 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Defensin 3D structures

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