| Abstract
| - New methods for the synthesis of artificial metalloenzymes are important for the construction ofnovel biocatalysts and biomaterials. Recently, we reported new methodology for the synthesis of artificialmetalloenzymes by reconstituting apo-myoglobin with metal complexes (Ohashi, M. et al., Angew Chem.,Int. Ed.2003, 42, 1005−1008). However, it has been difficult to improve their reactivity, since their crystalstructures were not available. In this article, we report the crystal structures of MIII(Schiff base)·apo-A71GMbs(M = Cr and Mn). The structures suggest that the position of the metal complex in apo-Mb is regulated by(i) noncovalent interaction between the ligand and surrounding peptides and (ii) the ligation of the metalion to proximal histidine (His93). In addition, it is proposed that specific interactions of Ile107 with 3- and3‘-substituent groups on the salen ligand control the location of the Schiff base ligand in the active site. Onthe basis of these results, we have successfully controlled the enantioselectivity in the sulfoxidation ofthioanisole by changing the size of substituents at the 3 and 3‘ positions. This is the first example of anenantioselective enzymatic reaction regulated by the design of metal complex in the protein active site.
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