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Arai, Shigeki; Yonezawa, Yasushi*; Okazaki, Nobuo*; Matsumoto, Fumiko*; Shibazaki, Chie; Shimizu, Rumi; Yamada, Mitsugu*; Adachi, Motoyasu; Tamada, Taro; Kawamoto, Masahide*; et al.
Acta Crystallographica Section D, 71(3), p.541 - 554, 2015/03
Times Cited Count:7 Percentile:50.44(Biochemical Research Methods)The crystal structure of halophilic -lactamase from
sp.560 (HaBLA) was determined using X-ray crystallography. Moreover, the locations of bound Sr
and Cs
ions were identified by anomalous X-ray diffraction. The location of one Cs
specific binding site was identified on HaBLA even in the presence of 9-fold molar excess of Na
(90 mM Na
/10 mM Cs
). This Cs
binding site is formed by two main-chain O atoms and an aromatic ring of a side chain of Trp. An aromatic ring of Trp interacts with Cs
by the cation-
interaction. The observation of a selective and high-affinity Cs
binding site provides important information that is useful for designing artificial Cs
binding sites useful in bioremediation of radioactive isotopes.
Arai, Shigeki; Adachi, Motoyasu; Tamada, Taro; Tokunaga, Hiroko*; Ishibashi, Matsujiro*; Tokunaga, Masao*; Kuroki, Ryota
no journal, ,
Because various metal ion binding sites exist on halophilic proteins, we proposed that the metal ion binding sites with an affinity to harmful metals and rare metals could be identified using X-ray crystallographic analysis in the presence of those metal ions. In this study, we attempted to identify metal ion binding sites for Sr and Cs
on a halophilic protein HaBLA derived from
sp.560 (HaBLA) by X-ray crystallographic analysis and anomalous X-ray diffraction analysis. By these analyses, we succeeded in discovering one Cs
binding site and three Sr
binding site for one molecule of HaBLA. Moreover, discovered Cs
binding site showed high Cs
selectivity, which binds Cs
even in the presence of 9-fold molar excess of Na
(90 mM Na
/ 10 mM Cs
).