Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exoenzyme C3stau2 from Staphylococcus aureus is a new member of the family of C3-like ADP-ribosyltransferases that ADP-ribosylates RhoA, -B, and -C. Additionally, it modifies RhoE and Rnd3. Here we report on studies of the structure-function relationship of recombinant C3stau2 by site-directed mutagenesis. Exchange of Glu(180) with leucine caused a complete loss of both ADP-ribosyltransferase and NAD glycohydrolase activity. By contrast, exchange of the glutamine residue two positions upstream (Gln(178)) with lysine blocked ADP-ribosyltransferase activity without major changes in NAD glycohydrolase activity. NAD and substrate binding of this mutant protein was comparable to that of the recombinant wild type. Exchange of amino acid Tyr(175), which is part of the recently described "ADP-ribosylating toxin turn-turn" (ARTT) motif [Han, S., Arvai, A. S., Clancy, S. B., and Tainer, J. A. (2001) J. Mol.Biol. 305, 95-107], with alanine, lysine, or threonine caused a loss of or a decrease in ADP-ribosyltransferase activity but an increase in NAD glycohydrolase activity. Recombinant C3stau2 Tyr175Ala and Tyr175Lys were not precipitated by matrix-bound Rho, supporting a role of Tyr(175) in protein substrate recognition. Exchange of Arg(48) and/or Arg(85) resulted in a 100-fold reduced transferase activity, while the recombinant C3stau2 double mutant R48K/R85K was totally inactive. The data indicate that amino acid residues Arg(48), Arg(85), Tyr(175), Gln(178), and Glu(180) are essential for ADP-ribosyltransferase activity of recombinant C3stau2 and support the role of the ARTT motif in substrate recognition of RhoA by C3-like ADP-ribosyltransferases.
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PMID:Structure-function analysis of the Rho-ADP-ribosylating exoenzyme C3stau2 from Staphylococcus aureus. 1181 47

The C3stau2 exoenzyme from Staphylococcus aureus is a C3-like ADP-ribosyltransferase that ADP-ribosylates not only RhoA-C but also RhoE/Rnd3. In this study we have crystallized and determined the structure of C3stau2 in both its native form and in complex with NAD at 1.68- and 2.02-A resolutions, respectively. The topology of C3stau2 is similar to that of C3bot1 from Clostridium botulinum (with which it shares 35% amino acid sequence identity) with the addition of two extra helices after strand beta1. The native structure also features a novel orientation of the catalytic ARTT loop, which approximates the conformation seen for the "NAD bound" form of C3bot1. C3stau2 orients NAD similarly to C3bot1, and on binding NAD, C3stau2 undergoes a clasping motion and a rearrangement of the phosphate-nicotinamide binding loop, enclosing the NAD in the binding site. Comparison of these structures with those of C3bot1 and related toxins reveals a degree of divergence in the interactions with the adenine moiety among the ADP-ribosylating toxins that contrasts with the more conserved interactions with the nicotinamide. Comparison with C3bot1 gives some insight into the different protein substrate specificities of these enzymes.
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PMID:The crystal structure of C3stau2 from Staphylococcus aureus and its complex with NAD. 1293 93

The novel C3-like ADP-ribosyltransferase is produced by a Staphylococcus aureus strain that especially ADP-ribosylates RhoE/Rnd3 subtype proteins, and its three-dimensional (3D) structure has not known. In order to understand the catalytic mechanism, the 3D structure of the protein is built by using homology modeling based on the known crystal structure of exoenzyme C3 from Clostridium botulinum (1G24). Then the model structure is further refined by energy minimization and molecular dynamics methods. The putative nicotinamide adenine dinucleotide (NAD(+))-binding pocket of exoenzyme C3(Stau) is determined by Binding-Site Search module. The NAD(+)-enzyme complex is developed by molecular dynamics simulation and the key residues involved in the combination of enzyme binding to the ligand-NAD(+) are determined, which is helpful to guide the experimental realization and the new mutant designs as well. Our results indicated that the key binding-site residues of Arg48, Glu180, Ser138, Asn134, Arg85, and Gln179 play an important role in the catalysis of exoenzyme C3(Stau), which is in consistent with experimental observation.
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PMID:Homology modeling and molecular dynamics studies of a novel C3-like ADP-ribosyltransferase. 1508 Sep 7