Laboratory of organic chemistry for life science

1 | Studies on structure-function relationships of proteins and creation of protein archaeology

Virtually every biological process in living cells is dictated by well organized functions of individual proteins involved. The function of each protein is closely associated with the tertiary structure defined solely by its amino acid sequence that is genetically encoded in the nucleotide sequence of DNA. Our main subjects include elucidation of primary and tertiary structures of proteins by using mass spectrometry. Analysis of proteins such as collagen and silk proteins remaining in archaeological specimens is one of the most challenging problems in our laboratory, because proteins are liable to degradation in natural environment. While devoting to analyzing silk proteins obtained from a material of the Asuka period (6-7th century AD), we felt as if we were time travelers who could talk to key figures in the history of ancient Japan. We are expecting to see many more famous people in world history.

Annealed at 110℃

Fig. 1 Loading a sample solution of a mixture of peptides prepared from a protein on a metal plate for mass spectrometry. To avoid contamination, keep your mouth shut! .

Fig. 2 Amino acid sequence analysis of peptide fragments of a protein of archaeological interest has revealed the existence of silk protein derived from a wild-type silkworm that is distinct from the domesticated bombyx mori.

2 | Fluorescent mercury sensors

We have been developing sensor molecules with quinoline moieties. The quinoline-containing moieties are expected to have attractive characteristics including fluorescence properties, recognition ability, and lipophilicity. However, many functions of quinolines as a sensor device still remain unexplored. Recently, we synthesized three BQET derivatives shown in the Figures. The compounds, BQET, 6-MeOBQET and TriMeOBQET, differ in only their methoxy substitution pattern, but exhibit metal-dependent OFF–ON, ratiometric and ON–OFF responses, respectively. Although complete discrimination between Hg(II) and Fe(III) is not yet achieved, the present research provides useful information for future fluorescent probe design strategies that lead to a metal ion specific response.

Heterogemini surfactants

Fig. 1 Structures of BQET derivatives and fluorescence response pattern toward the Hg(II) ion.

Amphiphilic dendrimers

Fig. 2 Searchlight for detection of Hg(II) (Image Illustration).

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