Magnetite (Fe3O4), a type of iron oxide crystal with strong magnetic properties, is used in bio-related products such as hard disks and MRI contrast agents. Chitons found in rocky coastal areas have extremely hard teeth made of magnetite on an organ called the radula that is used for feeding, but the mechanism of their formation was previously unknown.
A collaborative research team led by Associate Professor Michiko Nemoto from Okayama University discovered a novel protein involved in these "magnetite teeth" and revealed the mechanism by which they form in vivo. The team had previously identified multiple proteins contained in magnetite teeth. In this study, they analyzed genes in radular tissue from three chiton species and discovered protein genes common to all three species. Furthermore, they found a protein that exists only in chitons and named it "radular teeth matrix protein 1 (RTMP1)." They also elucidated the mechanism by which RTMP1 binds to chitin fibers, the pre-formed framework of the teeth, and induces the formation of iron oxide on the chitin fibers.
Currently, industrial synthesis of magnetite requires high temperatures and hazardous substances, but using RTMP1 could enable synthesis through safe and environmentally friendly methods. Additionally, it has been established that excess iron in the human body can cause cancer and neurodegenerative diseases. RTMP1, which can control iron, is expected to find applications in research for treating these diseases.
(Article: Masanori Nakajo)
