title: Experimental evidence for a beta beta alpha-Me-finger nuclease motif to represent the active site of the caspase-activated DNase.
abstract: The caspase-activated DNase (CAD) is an important nuclease involved in apoptotic DNA degradation. Results of a sequence comparison of CAD proteins with beta beta alpha-Me-finger nucleases in conjunction with a mutational and chemical modification analysis suggest that CAD proteins constitute a new family of beta beta alpha-Me-finger nucleases. Nucleases of this family have widely different functions but are characterized by a common active-site fold and similar catalytic mechanisms. According to our results and comparisons with related nucleases, the active site of CAD displays features that partly resemble those of the colicin E9 and partly those of the T4 endonuclease VII active sites. We suggest that the catalytic mechanism of CAD involves a conserved histidine residue, acting as a general base, and another histidine as well as an aspartic acid residue required for cofactor binding. Our findings provide a first insight into the likely active-site structure and catalytic mechanism of a nuclease involved in the degradation of chromosomal DNA during programmed cell death.
authors.affiliation: Institute of Biochemistry, Justus-Liebig-University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany.
authors.forename: Sebastian R
authors.initials: SR
authors.lastname: Scholz
authors.forename: Christian
authors.initials: C
authors.lastname: Korn
authors.forename: Janusz M
authors.initials: JM
authors.lastname: Bujnicki
authors.forename: Oleg
authors.initials: O
authors.lastname: Gimadutdinow
authors.forename: Alfred
authors.initials: A
authors.lastname: Pingoud
authors.forename: Gregor
authors.initials: G
authors.lastname: Meiss
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D001665:Binding Sites; D002234:Carbodiimides / Q000494:pharmacology; D002384:Catalysis; D002482:Cellulose / Q000378:metabolism; D003087:Colicins / Q000737:chemistry; D004247:DNA / Q000378:metabolism; D003851:Deoxyribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004720:Endonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D005982:Glutathione Transferase / Q000235:genetics; D006639:Histidine / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D016335:Zinc Fingers
chemical_list: D002234:Carbodiimides; D003087:Colicins; D011993:Recombinant Fusion Proteins; C074139:1-ethyl-3-(3-dimethylaminoethyl)carbodiimide; D006639:Histidine; D002482:Cellulose; D004247:DNA; D005982:Glutathione Transferase; D003851:Deoxyribonucleases; D004720:Endonucleases; C109663:caspase-activated deoxyribonuclease