title: Crystallization and preliminary X-ray analysis of human MTH1 with a homogeneous N-terminus.
abstract: Human MTH1 (hMTH1) is an enzyme that hydrolyses several oxidized purine nucleoside triphosphates to their corresponding nucleoside monophosphates. Crystallographic studies have shown that the accurate mode of interaction between 8-oxoguanine and hMTH1 cannot be understood without determining the positions of the H atoms, as can be observed in neutron and/or ultrahigh-resolution X-ray diffraction studies. The hMTH1 protein prepared in the original expression system from Escherichia coli did not appear to be suitable for obtaining high-quality crystals because the hMTH1 protein had heterogeneous N-termini of Met1 and Gly2 that resulted from N-terminal Met excision by methionine aminopeptidase from the E. coli host. To obtain homogeneous hMTH1, the Gly at the second position was replaced by Lys. As a result, mutant hMTH1 protein [hMTH1(G2K)] with a homogeneous N-terminus could be prepared and high-quality crystals which diffracted to near 1.1 Å resolution using synchrotron radiation were produced. The new crystals belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 46.36, b = 47.58, c = 123.89 Å.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Koga
authors.forename: Miyuki
authors.initials: M
authors.lastname: Inazato
authors.forename: Teruya
authors.initials: T
authors.lastname: Nakamura
authors.forename: Chie
authors.initials: C
authors.lastname: Hashikawa
authors.forename: Mami
authors.initials: M
authors.lastname: Chirifu
authors.forename: Asuka
authors.initials: A
authors.lastname: Michi
authors.forename: Taku
authors.initials: T
authors.lastname: Yamashita
authors.forename: Sachiko
authors.initials: S
authors.lastname: Toma
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kuniyasu
authors.forename: Shinji
authors.initials: S
authors.lastname: Ikemizu
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Nakabeppu
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Yamagata
mesh_terms: D019943:Amino Acid Substitution; D003460:Crystallization / Q000379:methods; D018360:Crystallography, X-Ray; D045643:DNA Repair Enzymes / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D005998:Glycine / Q000737:chemistry; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D008239:Lysine / Q000737:chemistry; D009154:Mutation; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D011487:Protein Conformation
chemical_list: C057674:8-hydroxyguanosine triphosphate; D006160:Guanosine Triphosphate; D010744:Phosphoric Monoester Hydrolases; C078207:8-oxodGTPase; D045643:DNA Repair Enzymes; D008239:Lysine; D005998:Glycine