Koga Y, Inazato M, Nakamura T, Hashikawa C, Chirifu M, Michi A, Yamashita T, Toma S, Kuniyasu A, Ikemizu S, Nakabeppu Y, Yamagata Y. Crystallization and preliminary X-ray analysis of human MTH1 with a homogeneous N-terminus.
Acta Crystallogr Sect F Struct Biol Cryst Commun 2012;
69:45-8. [PMID:
23295485 DOI:
10.1107/s1744309112048002]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 11/21/2012] [Indexed: 11/10/2022]
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.
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