The properties of the metal-thiolate clusters in recombinant mouse metallothionein-4.
Metallothioneins (MTs) are metal-binding proteins with low molecular weight and conservative cysteine residues. Metallothionein-4 (MT-4), one of MT isoforms, is first reported to be distributed in a tissue-specific manner, mainly in stratified squamous epithelia. Here, we compare the properties of metal-thiolate clusters in MT-4 to those in MT-1 and MT-3, including the stabilities toward both pH change and EDTA, as well as the exposure of thiolates to solvent. The metal-thiolate clusters in MT-3 show different property and activity to the reactions compared with MT-4 and MT-1. The structure of metal-thiolate clusters in MT-4 is similar to that of MT-1 from the UV and CD spectra. During pH titration and DTNB reaction, MT-4 and MT-1 exhibit comparable behavior. But while reacting with EDTA, the metal-thiolate clusters in MT-4 are more stable than those of MT-1. We suppose the negative charge of the beta-domain of MT-4 prevents the EDTA attack to MT-4.
Cai
Bin
B
Chemical Biology Lab, Department of Chemistry, Fudan University, Shanghai, 200433, China.
Zheng
Qi
Q
Huang
Zhong-Xian
ZX
D000818:Animals; D002942:Circular Dichroism; D004228:Dithionitrobenzoic Acid / Q000737:chemistry; D004492:Edetic Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008668:Metallothionein / Q000737:chemistry*; D000090023:Metallothionein 3; D051379:Mice; D009942:Organometallic Compounds / Q000737:chemistry*; D020033:Protein Isoforms / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D000090023:Metallothionein 3; C000715430:Mt3 protein, mouse; D009942:Organometallic Compounds; D020033:Protein Isoforms; D011994:Recombinant Proteins; D013438:Sulfhydryl Compounds; C509879:metallothionein-4, mouse; D008668:Metallothionein; D004228:Dithionitrobenzoic Acid; D004492:Edetic Acid