{"entry": {"accession": "MF7000257", "general": {"name": "MazG (Escherichia coli)", "pdb_id": "3cra", "exp_method": "X-ray", "resolution": "2.10", "assembly": "Homodimer", "source_organism": "Escherichia coli", "publication": {"pmid": "18353782", "authors": "Lee S, Kim MH, Kang BS, Kim JS, Kim GH, Kim YG, Kim KJ", "title": "Crystal structure of Escherichia coli MazG, the regulator of nutritional stress response.", "journal": "J. Biol. Chem.", "year": "2008", "issue": "22", "volume": "283", "pages": "15232-40", "abstract": "MazG is a nucleoside triphosphate pyrophosphohydrolase that hydrolyzes all canonical nucleoside triphosphates. The mazG gene located downstream from the chromosomal mazEF \"addiction module,\" that mediated programmed cell death in Escherichia coli. MazG activity is inhibited by the MazEF complex both in vivo and in vitro. Enzymatic activity of MazG in vivo affects the cellular level of guanosine 3',5'-bispyrophosphate (ppGpp), synthesized by RelA under amino acid starvation. The reduction of ppGpp, caused by MazG, may extend the period of cell survival under nutritional stress. Here we describe the first crystal structure of active MazG from E. coli, which is composed of two similarly folded globular domains in tandem. Among the two putative catalytic domains, only the C-terminal domain has well ordered active sites and exhibits an NTPase activity. The MazG-ATP complex structure and subsequent mutagenesis studies explain the peculiar active site environment accommodating all eight canonical NTPs as substrates. In vivo nutrient starvation experiments show that the C terminus NTPase activity is responsible for the regulation of bacterial cell survival under nutritional stress."}}, "function": {"molecular_function": {"go": [{"accession": "GO:0005524", "name": "ATP binding"}, {"accession": "GO:0047693", "name": "ATP diphosphatase activity"}, {"accession": "GO:0046872", "name": "metal ion binding"}, {"accession": "GO:0047429", "name": "nucleoside triphosphate diphosphatase activity"}]}, "biological_process": {"go": [{"accession": "GO:0009267", "name": "cellular response to starvation"}, {"accession": "GO:0046061", "name": "dATP catabolic process"}, {"accession": "GO:0006203", "name": "dGTP catabolic process"}, {"accession": "GO:0046076", "name": "dTTP catabolic process"}, {"accession": "GO:0046081", "name": "dUTP catabolic process"}, {"accession": "GO:0046047", "name": "TTP catabolic process"}, {"accession": "GO:0046052", "name": "UTP catabolic process"}]}}, "macromolecules": {"general": {"nr_of_chains": "2", "nr_of_unique_protein_segments": "1", "class": "Homooligomeric enzymes", "subclass": "Homodimeric enzymes", "note": "All chains according to the most probable oligomerization state stored in PDBe were considered."}, "chain": [{"id": "A", "name": "Nucleoside triphosphate pyrophosphohydrolase", "source_organism": "Escherichia coli", "uniprot": {"id": "P0AEY3", "start": "2", "end": "260", "coverage": "98%", "sequence": "MNQIDRLLTIMQRLRDPENGCPWDKEQTFATIAPYTLEETYEVLDAIAREDFDDLRGELGDLLFQVVFYAQMAQEEGRFDFNDICAAISDKLERRHPHVFADSSAENSSEVLARWEQIKTEERAQKAQHSALDDIPRSLPALMRAQKIQKRCANVGFDWTTLGPVVDKVYEEIDEVMYEARQAVVDQAKLEEEMGDLLFATVNLARHLGTKAEIALQKANEKFERRFREVERIVAARGLEMTGVDLETMEEVWQQVKRQEIDL", "length": "263"}, "regions": {"region": [{"region_type": "secondary structure", "region_name": "helix", "region_start": "4", "region_end": "18"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "25", "region_end": "29"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "30", "region_end": "51"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "53", "region_end": "77"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "82", "region_end": "96"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "116", "region_end": "126"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "142", "region_end": "156"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "163", "region_end": "184"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "188", "region_end": "210"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "213", "region_end": "239"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "250", "region_end": "261"}, {"region_type": "pfam", "region_id": "PF03819", "region_name": "MazG nucleotide pyrophosphohydrolase domain", "region_start": "27", "region_end": "100"}]}}, {"id": "B", "name": "Nucleoside triphosphate pyrophosphohydrolase", "source_organism": "Escherichia coli", "uniprot": {"id": "P0AEY3", "start": "2", "end": "261", "coverage": "98%", "sequence": "MNQIDRLLTIMQRLRDPENGCPWDKEQTFATIAPYTLEETYEVLDAIAREDFDDLRGELGDLLFQVVFYAQMAQEEGRFDFNDICAAISDKLERRHPHVFADSSAENSSEVLARWEQIKTEERAQKAQHSALDDIPRSLPALMRAQKIQKRCANVGFDWTTLGPVVDKVYEEIDEVMYEARQAVVDQAKLEEEMGDLLFATVNLARHLGTKAEIALQKANEKFERRFREVERIVAARGLEMTGVDLETMEEVWQQVKRQEIDL", "length": "263"}, "regions": {"region": [{"region_type": "secondary structure", "region_name": "helix", "region_start": "5", "region_end": "14"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "34", "region_end": "51"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "53", "region_end": "78"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "81", "region_end": "96"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "142", "region_end": "157"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "164", "region_end": "183"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "188", "region_end": "210"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "213", "region_end": "238"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "242", "region_end": "246"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "247", "region_end": "261"}, {"region_type": "pfam", "region_id": "PF03819", "region_name": "MazG nucleotide pyrophosphohydrolase domain", "region_start": "27", "region_end": "100"}]}}]}, "evidence": {"evidence_level": "Direct evidence", "evidence_coverage": "The full structure participates in mutual synergistic folding.", "sequence_domain": "MazG nucleotide pyrophosphohydrolase domain", "complex_evidence": "CD denaturatrion fits two state model. A four-state thermal denaturation model fits all data including DSC in (dimeric N2 native, two dimeric intermadiate I2,S2, and monomeric denatured D states). The authors state that both native like intermediete states are dimeric. Thermally denatured monomeric state is not fully unfolded and contains a significant fraction of residual \u03b1-helical structure (PMID:19523960).", "chain_evidence": [{"chain_id": "A", "support": "N/A"}, {"chain_id": "B", "support": "N/A"}]}, "related_structures": {"id": ["MF7000257", "MF7000258"]}}}