title: N-Terminal Cys-Rich Region of a Rice Type 1 Metallothionein Independently Forms Metal-Thiolate Cluster.
abstract: The members of plant metallothionein (MT) subfamily p1 are characterized with the presence of six Cys at each end of N- and C-terminal of their amino acid sequences which are arranged in a CXCXXXCXCXXXCXC and CXCXXXCXCXXCXC sequence, respectively. In this study we evaluated the independence of N-terminal Cys-rich region of a type 1 MT isoform from rice (OsMTI- 1b) in forming metal-thiolate cluster. To this end the N-terminal of OsMTI-1b (N-OsMTI-1b) was heterologously expressed in Escherichia coli as fusion protein with glutathione-S-transferase (GST). The E.coli cells expressing GST-N-OsMTI-1b were able to remove Cd2+ and Ni2+ from culture medium. The recombinant GST-N-OsMTI-1b was purified using affinity chromatography. The UV absorption spectra recorded after the reconstitution of the apo-protein with Cd2+ and Ni2+ confirmed that GST-N-OsMTI-1b was able to form complexes with Cd2+ and Ni2+. These results demonstrate the formation of independent metal-thiolate cluster at Nterminal Cys-rich region of GST-N-OsMTI-1b without participation of C-terminal Cys-rich region.
authors.forename: Soheila
authors.initials: S
authors.lastname: Ahmadi
authors.affiliation: Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan 84156- 83111, Iran. a.shahpiri@cc.iut.ac.ir.
authors.forename: Azar
authors.initials: A
authors.lastname: Shahpiri
mesh_terms: D000595:Amino Acid Sequence; D002104:Cadmium / Q000737:chemistry*; D002846:Chromatography, Affinity; D015870:Gene Expression; D005982:Glutathione Transferase / Q000737:chemistry / Q000235:genetics; D008668:Metallothionein / Q000737:chemistry* / Q000235:genetics; D009154:Mutation; D009532:Nickel / Q000737:chemistry*; D012275:Oryza / Q000737:chemistry* / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C407523:metallothionein isoform 1; D002104:Cadmium; D009532:Nickel; D008668:Metallothionein; D005982:Glutathione Transferase