TY - JOUR
T1 - The metal-binding features of the recombinant mussel Mytilus edulis MT-10-IV metallothionein
AU - Orihuela, Rubén
AU - Domènech, Jordi
AU - Bofill, Roger
AU - You, Chunhui
AU - Mackay, Elaine A.
AU - Kägi, Jeremias H.R.
AU - Capdevila, Mercè
AU - Atrian, Sílvia
PY - 2008/6/1
Y1 - 2008/6/1
N2 - In contrast with the paradigmatic mammalian metallothioneins (MTs), mollusc MT systems consist at least of a high-cadmium induced form, possibly involved in detoxification, and another isoform either constitutive or regulated by essential metals and probably associated with housekeeping metabolism. With the aim of providing a deeper characterization of the coordination features of a molluscan MT peptide of the latter kind, we have analyzed here the metal-binding abilities of the recombinant MeMT-10-IV isoform of Mytilus edulis (MeMT). Also, comparison with other MTs of this type has been undertaken. A synthetic complementary DNA was constructed, cloned and expressed into two Escherichia coli systems. Upon zinc coordination, MeMT folds in vivo into highly chiral and stable Zn7 complexes, with an exceptional reluctance to fully substitute cadmium(II) and/or copper(I) for zinc(II). In vivo cadmium binding leads to homometallic Cd7 complexes that structurally differ from any of the in vitro prepared Cd7 complexes. Homometallic Cu-MeMT can only be obtained in vitro from Zn7-MeMT after a great molar excess of copper(I) has been added. In vivo, two different heterometallic Zn,Cu-MeMT complexes are recovered, which nicely correspond to two distinct stages of the in vitro zinc/copper replacement. These MeMT metal-binding features are consistent with a physiological role related to basal/housekeeping metal, mainly zinc, metabolism, and confirm the correspondence between the MeMT gene response pattern and the functional properties of the encoded protein. © 2008 SBIC.
AB - In contrast with the paradigmatic mammalian metallothioneins (MTs), mollusc MT systems consist at least of a high-cadmium induced form, possibly involved in detoxification, and another isoform either constitutive or regulated by essential metals and probably associated with housekeeping metabolism. With the aim of providing a deeper characterization of the coordination features of a molluscan MT peptide of the latter kind, we have analyzed here the metal-binding abilities of the recombinant MeMT-10-IV isoform of Mytilus edulis (MeMT). Also, comparison with other MTs of this type has been undertaken. A synthetic complementary DNA was constructed, cloned and expressed into two Escherichia coli systems. Upon zinc coordination, MeMT folds in vivo into highly chiral and stable Zn7 complexes, with an exceptional reluctance to fully substitute cadmium(II) and/or copper(I) for zinc(II). In vivo cadmium binding leads to homometallic Cd7 complexes that structurally differ from any of the in vitro prepared Cd7 complexes. Homometallic Cu-MeMT can only be obtained in vitro from Zn7-MeMT after a great molar excess of copper(I) has been added. In vivo, two different heterometallic Zn,Cu-MeMT complexes are recovered, which nicely correspond to two distinct stages of the in vitro zinc/copper replacement. These MeMT metal-binding features are consistent with a physiological role related to basal/housekeeping metal, mainly zinc, metabolism, and confirm the correspondence between the MeMT gene response pattern and the functional properties of the encoded protein. © 2008 SBIC.
KW - Bivalve
KW - Metal metabolism
KW - Mollusca
KW - MT-10-IV
KW - Zinc, cadmium and copper binding
U2 - 10.1007/s00775-008-0367-6
DO - 10.1007/s00775-008-0367-6
M3 - Article
VL - 13
SP - 801
EP - 812
JO - Journal of Biological Inorganic Chemistry
JF - Journal of Biological Inorganic Chemistry
SN - 0949-8257
IS - 5
ER -