Structural analysis of bacterial metallothioneins involved in heavy metal detoxification

Microorganisms have developed many ways to circumvent heavy metal stress, mainly by synthesizing metallothionein-like proteins. Heavy metal pollution is a serious environmental concern because it lasts for a long time, is highly toxic and builds up in living organisms, posing risks to both ecosystems and human health. This microbial defense against heavy metal cytotoxicity can be proven to be a game-changer in heavy metal bioremediation if properly understood in terms of size, structure and biochemical nature. Hence, four bacterial metallothionein-related proteins, Smt, MymT and BmtA, were analysed. Data shows differences in size, stability and structure: larger proteins tended to be more stable with higher aliphatic indices, while smaller ones were more flexible and still preserved key metal-binding motifs. Thus, we show the structural and evolutionary features of these proteins to understand their roles in microbial metal detoxification and bioremediation.