Gene Cloning, Protein Expression and Functional Analysis of a type 3 Metallothionein with Bioaccumulation Potential from Sonneratia alba

Abstract

Sonneratia alba (S. alba) is a mangrove species grown in brackish water of tropical and subtropical regions. Due to its unique environment, it has evolved various mechanisms for modulating salt and metal levels. In order to find the genes connected with bioaccumulation of metals, the root transcriptome annotation of Sonneratia alba was analyzed and a new metallothionein (MT) gene was cloned. Sequence analysis found that the new MT gene belongs to type 3 MT, which is mostly expressed in roots. A simple and efficient method was used to express the type 3 MT of S. alba (SaMT3) by transforming the recombinant expression vector pET15b-SaMT3 into Escherichia coli (E. coli) Rosetta-gami and induction with the optimal conditions of 500 μM Isopropyl β-D-1-thiogalactopyranoside (IPTG) at 24ºC for 12 h. OD 600