The Effect Of Morphological Differences On The Mechanism Of Action Of Heavy Metals And Bovine Serum Albumin

Heavy metals exist in nature in different species.In order to understand the effects of different species of heavy metals on the body,the interaction mechanism of different species of heavy metals with proteins under separate and coexisting conditions and their effects on protein conformation were studied.The research results have certain reference significance for understanding the distribution,metabolism and toxicity of heavy metals in organisms.In this paper,a variety of spectroscopy methods combined with molecular docking technology were used to study the binding mechanism between three different species of heavy metals(antimony,manganese,chromium)and bovine serum albumin(BSA),and its impact on the secondary structure of BSA and the amino acid microenvironment.The main research contents are as follows:1.The toxicity of antimony(Sb)is closely related to its chemical species.The multispectral method was used to study the binding mechanism of antimony potassium tartrate and potassium pyroantimonate with BSA separately or simultaneously.The experimental results show that the fluorescence quenching of BSA by antimony potassium tartrate and potassium pyroantimonate are both static quenching,and both will form a 1:1 complex with BSA with a moderate binding force.At 298 K,the binding force of potassium pyroantimonate and BSA is greater than that of antimony potassium tartrate and BSA.Both antimony potassium tartrate and potassium pyroantimonate will change the secondary structure of BSA.Both antimony potassium tartrate and potassium pyroantimonate bind at site I of BSA.In the ternary system,the fluorescence quenching mechanism of antimony potassium tartrate/potassium pyroantimonate and BSA has not changed,and when antimony potassium tartrate and potassium pyroantimonate exist at the same time,Their binding force to BSA decreased,and the content of α-helix decreased more.This indicates that one species of Sb interferes with the binding of another species of Sb to BSA.2.To study the interaction mechanism of two valence states of manganese(Mn(Ⅱ)and Mn(Ⅲ))with BSA separately and simultaneously.The results show that the fluorescence quenching of BSA by Mn(Ⅱ)and Mn(Ⅲ)are both static quenching processes,that is,Mn(Ⅱ)-BSA and Mn(Ⅲ)-BSA complexes are formed.In contrast,the binding constant of Mn(Ⅲ)-BSA is greater than that of Mn(Ⅱ)-BSA,and the complex of Mn(Ⅲ)and BSA is more stable.Hydrophobic interaction is the main force of binding between Mn and BSA,and Mn(Ⅱ)/Mn(Ⅲ)will cause the conformational change of BSA.Compared with the binary system,the binding force of the ternary system is reduced,the binding distance is slightly increased,and the conformational change of BSA is greater.This indicates that both species of Mn will interfere with the binding of BSA.3.The interaction mechanism of inorganic chromium(Cr(Ⅲ)and Cr(Ⅵ))and organic chromium(chromium picolinate(Crpic))with BSA was studied.Spectral analysis shows that the fluorescence quenching of BSA by Cr(Ⅲ)and Cr(Ⅵ)is static quenching,while the fluorescence quenching of BSA by Crpic is a mixed process of dynamic quenching and static quenching.At 298 K,the binding force between the three is Cr(Ⅵ)>Crpic>Cr(Ⅲ).Cr(Ⅲ),Cr(Ⅵ)or Crpic will cause the conformational changes of BSA,but the degree of influence is different.Cr(Ⅵ)has the greatest influence on the content ofα-helix,followed by Crpic and Cr(Ⅲ),followed by Crpic and Cr(Ⅲ),and the microenvironment around the amino acid residues is changed.Hydrogen bond and van der Waals force are the main binding force between Cr(Ⅵ)and BSA;hydrophobic effect is the main binding force between Crpic and BSA;electrostatic force and van der Waals force are the main binding force between Cr(Ⅲ)and BSA.In the ternary system,the competition of Cr(Ⅵ)and Cr(Ⅲ)with BSA reduces the binding affinity of Cr(Ⅵ)and BSA,and Cr(Ⅲ)changes the type of force between Cr(Ⅵ)and BSA.However,the binding competition between Crpic and Cr(Ⅲ)and BSA increased the binding affinity of Crpic and BSA.And the existence of Cr(Ⅲ)has a greater impact on the secondary structure of Cr(Ⅵ)/Crpic-BSA.Cr(Ⅲ)will affect the combination of Cr(Ⅵ)/Crpic and BSA.