Research
Homochirality of Life
Chirality is a property of objects that are non-superimposable on their mirror image. The two forms of a chiral object are called enantiomers.
Homochirality is a situation where either enantiomer dominates the other one.
Mysteriously, living organisms utilize only a single enantiomer in each biological process. There are two major facts relating to the homochirality of biological molecules: most natural sugars are D-sugars and most natural amino acids are L-amino acids. Living organisms enatioselectively utilize L-amino acids as the molecular architecture of protein synthesized in the ribosome. Although L-amino acids are dominantly employed in most biological processes, accumulating evidence point to the distinctive roles of D-amino acids in non-ribosomal physiology.
Major exceptions of amino acid homochirality
Among all domains of life, bacteria have the largest capacity to produce wide variety of D-amino acids, whereas archaea and eukaryotes are thought to synthesize generally two kinds of D-amino acids, D-serine and D-aspartate. Bacteria utilize diverse D-amino acids in multiple biological processes to support their growth, to regulate spore germination, and to configure or remodel their cell wall. In contrast, mammals utilize D-serine in neurophysiology and D-aspartate in neurogenesis and endocrine systems. Furthermore, in mammals, commensal and pathogenic microbiota produce various D-amino acids, which play roles in the host physiology including a role in the host innate defense.
Our Focus
We are exploring roles of intrinsic and microbial D-amino acids in the mammalian physiology and pathology especially in 1) the host-microbe interactions, 2) the central nervous system, and 3) systemic energy metabolism. Our group seeks to apply this to human health and disease.