diadenosine 5',5'''-P1,P6-hexaphosphate hydrolase type 2 and similar proteins; Diadenosine 5',5'''-P1,P6-hexaphosphate hydrolase type 2 (DIPP2), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 4; Nudt4, and other proteins including DIPP1/Nudt3, DIPP3a;APS2/Nudt10 and DIPP3beta;APS1/Nudt11. DIPP regulates the turnover of diphosphoinositol polyphosphates. The turnover of these high-energy diphosphoinositol polyphosphates represents a molecular switching activity with important regulatory consequences. Molecular switching by diphosphoinositol polyphosphates may contribute to regulating intracellular trafficking. Several alternatively spliced transcript variants have been described, but the full-length nature of some variants has not been determined. Isoforms DIPP2alpha and DIPP2beta are distinguishable from each other solely by DIPP2beta possessing one additional amino acid due to intron boundary skidding in alternate splicing. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGK-LGRLLGIFEQNQDR-----KHRTYVYVLTVTEILEDWEDSVniGRKREWFKVEDA 74
Cdd:cd04666   35 PEKGETPAEAAAREAWEEAGVRGKvLKRPLGVYRYRKRLkgrglPCRVHVFPLEVTEELDDWPEKH--ERKRRWFSPEEA 112

                         90
                 ....*....|....*...
gi 666335637  75 IKVLQchKPVHAEYLEKL 92
Cdd:cd04666  113 AELVD--EPELRELLRRL 128

diadenosine 5',5'''-P1,P6-hexaphosphate hydrolase type 2 and similar proteins; Diadenosine 5',5'''-P1,P6-hexaphosphate hydrolase type 2 (DIPP2), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 4; Nudt4, and other proteins including DIPP1/Nudt3, DIPP3a;APS2/Nudt10 and DIPP3beta;APS1/Nudt11. DIPP regulates the turnover of diphosphoinositol polyphosphates. The turnover of these high-energy diphosphoinositol polyphosphates represents a molecular switching activity with important regulatory consequences. Molecular switching by diphosphoinositol polyphosphates may contribute to regulating intracellular trafficking. Several alternatively spliced transcript variants have been described, but the full-length nature of some variants has not been determined. Isoforms DIPP2alpha and DIPP2beta are distinguishable from each other solely by DIPP2beta possessing one additional amino acid due to intron boundary skidding in alternate splicing. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGK-LGRLLGIFEQNQDR-----KHRTYVYVLTVTEILEDWEDSVniGRKREWFKVEDA 74
Cdd:cd04666   35 PEKGETPAEAAAREAWEEAGVRGKvLKRPLGVYRYRKRLkgrglPCRVHVFPLEVTEELDDWPEKH--ERKRRWFSPEEA 112

                         90
                 ....*....|....*...
gi 666335637  75 IKVLQchKPVHAEYLEKL 92
Cdd:cd04666  113 AELVD--EPELRELLRRL 128

NUDIX domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 666335637    1 MEPEEEPGGAAVREVYEEAGVKGKLGRLLGIFEQNQ-------DRKHRTYVYVLTVTEILE-DWEDSVnigRKREWFKVE 72
Cdd:pfam00293  38 VEPGETPEEAARRELEEETGLEPELLELLGSLHYLApfdgrfpDEHEILYVFLAEVEGELEpDPDGEV---EEVRWVPLE 114

                          90       100
                  ....*....|....*....|
gi 666335637   73 DAikVLQCHKPVHAEYLEKL 92
Cdd:pfam00293 115 EL--LLLKLAPGDRKLLPWL 132

diadenosine 5',5'''-P1,P6-hexaphosphate hydrolase type 2 and similar proteins; Diadenosine 5',5'''-P1,P6-hexaphosphate hydrolase type 2 (DIPP2), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 4; Nudt4, and other proteins including DIPP1/Nudt3, DIPP3a;APS2/Nudt10 and DIPP3beta;APS1/Nudt11. DIPP regulates the turnover of diphosphoinositol polyphosphates. The turnover of these high-energy diphosphoinositol polyphosphates represents a molecular switching activity with important regulatory consequences. Molecular switching by diphosphoinositol polyphosphates may contribute to regulating intracellular trafficking. Several alternatively spliced transcript variants have been described, but the full-length nature of some variants has not been determined. Isoforms DIPP2alpha and DIPP2beta are distinguishable from each other solely by DIPP2beta possessing one additional amino acid due to intron boundary skidding in alternate splicing. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGK-LGRLLGIFEQNQDR-----KHRTYVYVLTVTEILEDWEDSVniGRKREWFKVEDA 74
Cdd:cd04666   35 PEKGETPAEAAAREAWEEAGVRGKvLKRPLGVYRYRKRLkgrglPCRVHVFPLEVTEELDDWPEKH--ERKRRWFSPEEA 112

                         90
                 ....*....|....*...
gi 666335637  75 IKVLQchKPVHAEYLEKL 92
Cdd:cd04666  113 AELVD--EPELRELLRRL 128

NUDIX hydrolase superfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*...
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGKLGRLLGIFEQNQDRKHRTYVYVLTVTEILEDWED 58
Cdd:cd02883   35 VEPGETPEEAAVREVREETGLDVEVLRLLGVYEFPDPDEGRHVVVLVFLARVVGGEPP 92

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGKLG-RLLGIFEQNQDRKHRTYVYVLTVTEIL-EDWEDSVNIGRKRE-------WFKV 71
Cdd:cd04663   35 VEPGESPEEAALRELAEETGLTGARVvVDLGSHDEGFEELHQRWFFHLCLAGEPpERWEHHETDDGEGGglrfeffWVPL 114

                         90       100
                 ....*....|....*....|.
gi 666335637  72 EDAIKVLQchkPVHAEYLEKL 92
Cdd:cd04663  115 AAAPPRLA---AGFGAALELL 132

8-oxo-dGTP pyrophosphatase MutT and related house-cleaning NTP pyrophosphohydrolases, NUDIX family [Defense mechanisms];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGKLGRLLGIFEQNQDRKHRTYVYVLTVTEILEDwedsVNIGRKRE-----WFKVEDAI 75
Cdd:COG0494   49 IEPGESPEEAALRELREETGLTAEDLELLGELPSPGYTDEKVHVFLARGLGPGEE----VGLDDEDEfievrWVPLDEAL 124

                 ...
gi 666335637  76 KVL 78
Cdd:COG0494  125 ALV 127

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30
                 ....*....|....*....|....*....|.
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGKLGRLLGI 31
Cdd:cd18879   50 VEPGEQPADAAVREVLEETGVDVEVERLASV 80

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30
                 ....*....|....*....|....*....|.
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGKLGRLLGI 31
Cdd:cd18876   32 VEAGESPLQAARREVREELGLDVPVGRLLAV 62

UDP-X diphosphatase; UDP-X diphosphatase hydrolyzes UDP-N-acetylmuramic acid and UDP-N-acetylmuramoyl-L-alanine, the last step of the Mur pathway of peptidoglycan biosynthesis. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|
gi 666335637   7 PGGAA----------VREVYEEAGVKGKLGRLLGIFEQNQ 36
Cdd:cd18891   29 PGGFAevglspkeniLKEVKEETGLHVEVERLLAVFDTDL 68

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGKLGRLLGIFeqnqDRKHRTYVYVLTVTEILED 55
Cdd:cd04511   36 MELGETTEQGAARETREEAGARVEIGSLYAVY----SLPHISQVYIIFRARLLSP 86

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGKLGRLLGIFEQNQDrkHRTY-----VYVLTVTEILEDWEDSVNI 62
Cdd:cd04677   44 MELGESLEETARREVFEETGLTVEELELLGVYSGKDL--YYTYpngdeVYNVTAVYLVRDVSGELKV 108

MutT homolog-1 and similar proteins; MutT homolog-1 (MTH1), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 1/Nudt1, is a member of the NUDIX hydrolase superfamily. MTH1, the mammalian counterpart of MutT, hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP and 2-hydroxy-ATP, to monophosphates, thereby preventing the incorporation of such oxygen radicals during replication. This is an important step in the repair mechanism in genomic and mitochondrial DNA. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity, and contain the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. MTH1 is predominantly localized in the cytoplasm and mitochondria. Structurally, this enzyme adopts a similar fold to MutT despite low sequence similarity outside the conserved NUDIX motif. The most distinctive structural difference between MutT and MTH1 is the presence of a beta-hairpin, which is absent in MutT. This results in a much deeper and narrower substrate binding pocket. Mechanistically, MTH1 contains dual specificity for nucleotides that contain 2-OH-adenine bases and those that contain 8-oxo-guanine bases.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGKLGRLLGIFEQNQDRKHRT-YVYVLTVTEILEDWEDSVNIGRkREWFKVED 73
Cdd:cd18886   34 LEPGESPEECAIREVFEETGLELEDLQLRGIVTFPSFDGGEDwLMYVFLAEAFSGELVESDREGI-LAWVPIDW 106

ADP-ribose pyrophosphatase, UDP-glucose pyrophosphatase, and similar proteins; ADP-ribose pyrophosphatase (ADPRase) ( NUDIX (Nucleoside diphosphate-linked moiety X)) motif 5; Nudt5) catalyzes the hydrolysis of ADP-ribose and a variety of additional ADP-sugar conjugates to AMP and ribose-5-phosphate. In humans, there are four distinct ADPRase activities, three putative cytosolic enzymes (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). Human ADPRase-II is also referred to as NUDT5. It lacks the N-terminal target sequence unique to mitochondrial ADPRase. The different cytosolic types are distinguished by their specificities for substrate and specific requirement for metal ions. NUDT5 forms a homodimer. It also contains a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. UDP-glucose pyrophosphatase (UGPPase) (EC 3.6.1.45; also known as nucleoside diphosphate-linked moiety X)) motif 14; Nudt14) hydrolyzes the pyrophosphate of the nucleoside diphosphate sugar to generate glucose-1-P and UMP. In mammals, UDP-glucose is the glucosyl donor for the synthesis of the storage polysaccharide glycogen. UGPPase, as a regulator of UDP-glucose, could play a regulatory role, but it has been shown to prefer ADP-ribose over UDP-glucose. Like other members of the NUDIX hydrolase superfamily, it requires a divalent cation, such as Mg2+, for its activity. It also contains a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site.

                         10        20        30
                 ....*....|....*....|....*....|..
gi 666335637   1 MEPEEEPGGAAVREVYEEAGVKGKLGRLLGIF 32
Cdd:cd03424   38 IDPGEDPEEAARRELEEETGYTAGDLELLGSF 69