Identification of regulatory domains in ADP-ribosyltransferase-1 that determine transferase and NAD glycohydrolase activities.
Mono-ADP-ribosyltransferases (ART1-7) transfer ADP-ribose from NAD+ to proteins (transferase activity) or water (NAD glycohydrolase activity). The mature proteins contain two domains, an alpha-helical amino terminus and a beta-sheet-rich carboxyl terminus. A basic region in the carboxyl termini is encoded in a separate exon in ART1 and ART5. Structural motifs are conserved among ART molecules. Successive amino- or carboxyl-terminal truncations of ART1, an arginine-specific transferase, identified regions that regulated transferase and NAD glycohydrolase activities. In mouse ART1, amino acids 24-38 (ART-specific extension) were needed to inhibit both activities; amino acids 39-45 (common ART coil) were required for both. Successive truncations of the alpha-helical region reduced transferase and NAD glycohydrolase activities; however, truncation to residue 106 enhanced both. Removal of the carboxyl-terminal basic domain decreased transferase, but enhanced NAD glycohydrolase, activity. Thus, amino- and carboxyl-terminal regions of ART1 are required for transferase activity. The enhanced glycohydrolase activity of the shorter mutants indicates that sequences, which are not part of the NAD binding, core catalytic site, exert structural constraints, modulating substrate specificity and catalytic activity. These functional domains, defined by discrete exons or structural motifs, are found in ART1 and other ARTs, consistent with conservation of structure and function across the ART family.
Pulmonary-Critical Care Medicine Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1590, USA. bougeoc@nhlbi.nih.gov
Christelle
C
Bourgeois
Ian
I
Okazaki
Eleanor
E
Cavanaugh
Maria
M
Nightingale
Joel
J
Moss
D036002:ADP Ribose Transferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000376:Agmatine / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020134:Catalytic Domain / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D066298:In Vitro Techniques; D051379:Mice; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism; D009244:NAD+ Nucleosidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D017931:DNA Primers; D011994:Recombinant Proteins; D009243:NAD; D000246:Adenosine Diphosphate Ribose; D000376:Agmatine; D036002:ADP Ribose Transferases; D009244:NAD+ Nucleosidase