title: Structural and functional characterization of a noncanonical nucleoside triphosphate pyrophosphatase from Thermotoga maritima.
abstract: The hyperthermophilic bacterium Thermotoga maritima has a noncanonical nucleoside triphosphatase that catalyzes the conversion of inosine triphosphate (ITP), deoxyinosine triphosphate (dITP) and xanthosine triphosphate (XTP) into inosine monophosphate (IMP), deoxyinosine monophosphate (IMP) and xanthosine monophosphate (XMP), respectively. The k(cat)/K(m) values determined at 323 and 353 K fall between 1.31 × 10(4) and 7.80 × 10(4) M(-1) s(-1). ITP and dITP are slightly preferred over XTP. Activity towards canonical nucleoside triphosphates (ATP and GTP) was not detected. The enzyme has an absolute requirement for Mg(2+) as a cofactor and has a preference for alkaline conditions. A protein X-ray structure of the enzyme with bound IMP was obtained at 2.15 Å resolution. The active site houses a well conserved network of residues that are critical for substrate recognition and catalysis. The crystal structure shows a tetramer with two possible dimer interfaces. One of these interfaces strongly resembles the dimer interface that is found in the structures of other noncanonical nucleoside pyrophosphatases from human (human ITPase) and archaea (Mj0226 and PhNTPase).
authors: Chemistry and Biochemistry, California State University East Bay, 25800 Carlos Bee Boulevard, Hayward, CA 94542, USA.
authors: Khaldeyah
authors: K
authors: Awwad
authors: Anna
authors: A
authors: Desai
authors: Clyde
authors: C
authors: Smith
authors: Monika
authors: M
authors: Sommerhalter
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D018360:Crystallography, X-Ray; D006801:Humans; D014176:Protein Biosynthesis; D011487:Protein Conformation; D011755:Pyrophosphatases / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D011897:Random Allocation; D020124:Thermotoga maritima / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011755:Pyrophosphatases; C021895:nucleoside triphosphate pyrophosphatase
keywords: Thermotoga maritima; dimer interface; enzymes; noncanonical nucleoside triphosphate pyrophosphatase; nucleotide metabolism
references: Acta Crystallogr D Biol Crystallogr. 2010 Jan;66(Pt 1):22-5
references: 20057045
references: Biochem Pharmacol. 1997 Sep 1;54(5):551-62
references: 9337071
references: Acta Crystallogr D Biol Crystallogr. 2011 Apr;67(Pt 4):355-67
references: 21460454
references: J Struct Biol. 2010 Jun;170(3):532-9
references: 20353826
references: J Biol Chem. 2001 Jun 1;276(22):18695-701
references: 11278832
references: Biochem Mol Biol Educ. 2007 Jul;35(4):293-7
references: 21591108
references: Acta Crystallogr D Biol Crystallogr. 2010 Feb;66(Pt 2):125-32
references: 20124692
references: Curr Opin Struct Biol. 1996 Jun;6(3):377-85
references: 8804824
references: BMC Bioinformatics. 2010 May 27;11:286
references: 20507585
references: J Biol Chem. 2007 Feb 9;282(6):3531-8
references: 17090528
references: J Appl Crystallogr. 2002 Dec;35(6):720-726
references: 24899734
references: Acta Crystallogr D Biol Crystallogr. 1999 Jan;55(Pt 1):247-55
references: 10089417
references: Biochemistry. 1968 Jan;7(1):448-55
references: 5758560
references: J Mol Biol. 2008 Jan 25;375(4):1013-25
references: 18062990
references: J Mol Biol. 2009 Sep 25;392(3):602-13
references: 19631656
references: Acta Crystallogr D Biol Crystallogr. 1997 May 1;53(Pt 3):240-55
references: 15299926
references: Nucleic Acids Res. 1993 Feb 11;21(3):777-8
references: 8441702
references: J Biol Chem. 2007 Nov 16;282(46):33572-33582
references: 17848562
references: Trends Biochem Sci. 2000 Jun;25(6):300-2
references: 10838572
references: Structure. 2005 Oct;13(10):1511-20
references: 16216582
references: J Biol Chem. 2007 Feb 2;282(5):3182-7
references: 17138556
references: Acta Crystallogr Sect F Struct Biol Cryst Commun. 2006 Nov 1;62(Pt 11):1076-81
references: 17077483
references: J Mol Biol. 2007 Dec 7;374(4):1091-103
references: 17976651
references: Cell Mol Life Sci. 2008 Apr;65(7-8):1059-72
references: 18080088
references: J Mol Biol. 2007 Sep 21;372(3):774-97
references: 17681537
references: Cell Mol Life Sci. 2001 Aug;58(9):1216-33
references: 11577980
references: Proc Natl Acad Sci U S A. 2000 Jun 6;97(12):6328-33
references: 10841541
references: J Cell Physiol. 1979 Jun;99(3):287-301
references: 457791
references: Eur J Biochem. 1974 Jan 16;41(2):209-16
references: 4816894
references: J Mol Biol. 2006 Feb 17;356(2):547-57
references: 16375925
references: Mol Microbiol. 2006 Jan;59(1):5-19
references: 16359314
references: Chem Soc Rev. 2009 Aug;38(8):2465-94
references: 19623361
references: Acta Crystallogr D Biol Crystallogr. 2004 Oct;60(Pt 10):1816-23
references: 15388928
references: Nucleic Acids Res. 1996 Dec 15;24(24):5021-5
references: 9016675
references: Nat Struct Biol. 1999 Jul;6(7):691-6
references: 10404228
references: Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 1):2126-32
references: 15572765
references: Nucleic Acids Res. 2001 Jul 15;29(14):3099-107
references: 11452035
references: J Biol Chem. 2001 Sep 21;276(38):35422-8
references: 11451960