X-ray crystallographic analysis of -Lactamase derived from sp.560

Arai, Shigeki; Tokunaga, Hiroko*; Tamada, Taro; Yonezawa, Yasushi; Adachi, Motoyasu; Yamada, Mitsugu; Ishibashi, Matsujiro*; Tokunaga, Masao*; Kuroki, Ryota

Halophilic proteins can bind various inorganic ions with its negative charges located over the molecular surface. We are investigating the molecular structure of the halophilic proteins because halophilic proteins might be used as a material capturing for the rare metals and/or the radioactive metal ions. Recently, we succeeded in X-ray crystallographic analysis of the halophilic -Lactamase (HaBLA) derived from sp.560 at 3.0 resolution. From this structural analysis, we found that the back bone structure and the positively charged active site feature of HaBLA was similar to those of non-halophilic BLA. The molecular surface of HaBLA were, however, occupied by large number of negative charges. This structural information is very useful to improve the specificity of metals such as Cs or Sr.