Laboratory of Biopolymer Chemistry (IMRAM)
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Metallo proteins, Heme proteins, Protein structures, Gas sensors, Protein synthesis
In an attempt to understand the structure-function relationships of heme-sensor proteins: . Heme-bound phosphodiesterase toward c-di-GMP, Ec DOS, . Heme-bound kinase involved in globin translation, HRI, . Heme-bound transcriptional factors associated with circadian rhythms, NPAS2, and Period, we are using genetic and protein engineering techniques, spectroscopies, and X-ray crystallography. Our goal is to redesign the proteins and enzymes and construct modifier versions with novel functions useful for biomaterials, biomedical and bioremedial applications.
1) Elucidation of the heme-binding site of heme-regulated eIF2α kinase (HRI) and the role of the regulatory motif in heme sensing by spectroscopic and catalytic studies of mutant proteins, J. Igarashi, M. Murase, A. Iizuka, F. Pichierri, M. Matinkova, and T. Shimizu, J. Biol. Chem. 2008, 283, 18782-18791.
2) Ligand binding to the Fe(III)-protoporphyrin IX complex of phosphodiesterase from Escherichia coli (Ec DOS) markedly enhances catalysis of cyclic di-GMP: Roles of Met95, Arg97, and Phe113 of the putative heme distal side in catalytic regulation and ligand binding, A. Tanaka, and T. Shimizu, Biochemistry 2008, 47, 13438-13446.
3) Heme binding characteristics of the isolated PAS-A domain of mouse Per2, a transcriptional regulatory factor associated with circadian rhythms, K. Kitanishi, J. Igarashi, K. Hayasaka, N. Hikage, I. Saiful, S. Yamauchi, T. Uchida, K. Ishimori, and T. Shimizu, Biochemistry 2008, 47, 6157-6168.