In this paper, the naturally occurred polymerization for rabbit metallothionein monomers has been studied in different milieu, while leaves out the aggregation caused by the oxidation of cysteine, since the latter circumstance was the result of purification lapsus. After the purification of metallothionein monomers, dynamic light scattering technique is used to detect the polymerized states of rabbit liver metallothionein Ⅰ and Ⅱ in different buffers, which is the first systematical detection of polymerized states of MTs in solutions. The effects of different factors contributing to methothionein aggregations have been investigated by computational simulations. The calculation results showed that the metallothionein polymerization would be regulated by many factors including electrostatic interactions, hydrophobic interactions and different ions in buffers. A molecular recognition mechanism of MTs polymerization in solutions is proposed on the bases of experimental results and theoretical calculations.
It has been proven by experiments that cations play a very important role in metallothioneins polymerization. In this paper, three kinds of metallothioneines including MT-Ⅱfrom rat liver, MT-Ⅰand MT-Ⅱfrom rabbit have been investigated.From the analyses of electrostatic potential, two binding sites of cations can be determined:The first one is located between the dimer interface; the other one is located in the negative electrostatic potential hole.The binding capacity between two monomers in a dimer can be regulated by these cations to some extent.
Metallothionein\|Ⅱ,6 8kDa,purified from the liver of rabbit induced by cadmium,has been crystallized in the space group P6 322 using hanging drop vapor diffusion method,with unit cell parameters a=b=113 4 ?, c =146 6?.There are 8 molecules per asymmetric unit and a solvent content of 58%.
