Study on Expression of Metallothionein and Nitric Oxide Synthase in Bacteria Isolated from Coal Mine Area Drained with Heavy Metals

Abstract

Metallothioneins (MTs) are a group of low molecular mass, cysteine-rich proteins with a variety of functions including involvement in metal homeostasis, free radical scavenging, protection against heavy metal damage and metabolic regulation via Zn donation. Besides, levels of MTs in invertebrates and aquatic vertebrates well correlate with heavy metal pollution of an environment and, thus, serve as bio-environmental marker. It is not surprising that these proteins are of great interest not only for biochemists, molecular biologists, clinical chemists but also for environmental chemists and ecologists. Detection and quantification of MTs, which is needed in all above mentioned areas is challenging due to the high cysteine content and relatively low molecular mass. The main objective of this study was to isolate and extract metallothionein from the bacterial culture isolated from the coal mining areas, since the micro-organisms present in the soil of these areas are naturally exposed to a number of various heavy metals as drainage from the coal mines and further to study the thiol content and hence the expression of metallothionein by SDS PAGE in presence of two divalent heavy metal ions.

Nitric oxide synthase (NOS) binds transition metals and demonstrates increment in expression of NOS activity in presence of metal like chromium. In this study the effects of metals on the activity of NOS and the effects of NOS on the thiol content of proteins were observed in bacterial culture isolated from coal mine area.

Finally an attempt was made there to establish any type of relationship between NOS and MT in the above study.