Three-dimensional crystal structure of human eosinophil cationic protein (RNase 3) at 1.75 A resolution.
Eosinophil cationic protein (ECP; RNase 3) is a human ribonuclease found only in eosinophil leukocytes that belongs to the RNase A superfamily. This enzyme is bactericidal, helminthotoxic and cytotoxic to mammalian cells and tissues. The protein has been cloned, heterologously overexpressed, purified and crystallized. Its crystal structure has been determined and refined using data up to 1. 75 A resolution. The molecule displays the alpha+beta folding topology typical for members of the ribonuclease A superfamily. The catalytic active site residues are conserved with respect to other ribonucleases of the superfamily but some differences appear at substrate recognition subsites, which may account, in part, for the low catalytic activity. Most strikingly, 19 surface-located arginine residues confer a strong basic character to the protein. The high concentration of positive charges and the particular orientation of the side-chains of these residues may also be related to the low activity of ECP as a ribonuclease and provides an explanation for its unique cytotoxic role through cell membrane disruption.
Mallorquí-Fernández
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Institut de Biologia Molecular de Barcelona, C.I.D-C.S.I.C, Jordi Girona, 18-26, Barcelona, 08034, Spain.
Pous
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Peracaula
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Aymamí
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Maeda
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Tada
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Yamada
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Seno
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de Llorens
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Gomis-Rüth
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Coll
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D000595:Amino Acid Sequence; D001120:Arginine / Q000378:metabolism; D001665:Binding Sites; D001798:Blood Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004220:Disulfides / Q000378:metabolism; D047150:Eosinophil Cationic Protein; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000201:enzymology*; D004926:Escherichia coli; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012260:Ribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D055672:Static Electricity; D013329:Structure-Activity Relationship
D001798:Blood Proteins; D004220:Disulfides; D047091:Eosinophil Granule Proteins; D011994:Recombinant Proteins; D001120:Arginine; D012260:Ribonucleases; D047150:Eosinophil Cationic Protein; C479220:RNASE3 protein, human