Expression of Mammalian Meallothionein-I Gene in Cyanobacteria to Enhance Heavy Metal Resistance

摘要

Metallothionein (MT) from mammals is a low molecular weight (about 6-7 KD), and cystein-rich (20 cystein per molecular) protein (Vallee, 1991). So MT has the strong binding ability of metal such as Cd, Hg and Pd. Wild- type cyanobacteria have their own metallothionein-like proteins, which are of low cysteine content and have weak ability to bind heavy metal. Therefore, it is imperative to transfer the MT-I gene from mammal into cyanobacteria cell for the absorption and accumulation of heavy metals in aqueous system including marine and lake (Misra and Gedamu, 1989).