Mechanism Of Microcystins And Its Derivatives Inhibited The Biological Activity Of Protein Phosphatase 1

Microcystins?MCs?,a world-wide health threat to humans and animals due to their increasing presence in aquatic environments as well as in water distribution systems.The primary target for MCs is the liver,as orally ingested MCs are actively absorbed to hepatic cells via a bile-acid transporter.Within the cells,MCs irreversibly inhibit several protein phosphatases?PPs?,subsequently leading to cell disruption,intrahepatic hemorrhage and death.For example,there are more than 80 kinds of MCs,so the mechanism of inhibition on PP1 was different.In the conventional of drinking water treatment process,the traditional chlorine disinfection process will bring a large number of disinfection by-products and microcystin characteristics of disinfection by-products.In the process of chlorine disinfection,the conjugated olefins on the MCs Adda5 residue and the carbon-carbon double bonds on the Mdha7 residue are affected by chlorine or other higher oxides to produce microcystin specificity disinfection by-products,resulting in secondary contamination.With regard to the removal of microcystins is a hot topic,while the use of bio-technology,via the conjugate of GSH and MCs,to control toxicity of microcystins also have been more and more researchers of all ages,it is the current prospects for a kind of better research for the regulation and treatment technology of microcystins.Based on the study of the eutrophication of water bodies and the characteristics of MCs pollution,physical and chemical structure,mechanism of toxic effects and regulation strategy,the structural characteristics of MCs/MCLR-DBPs/MC-GSHs and PP1 conjugates were analyzed by molecular docking simulation.The theoretical data were compared with the of toxicity test.The MCs/MCLR-DBPs/MC-GSHs were inhibited the bio-activity of PP1.The toxicity of toxin on the biological activity of PP1 was further analyzed by using the molecular dock simulation,so as to provide a basis theoretical for the regulation of MCs.The specific work all as follow:?1?Study on the mechanism of Microcystins homologue inhibited the biological activity of PP1.In this study,MCLR as the based comparative studies were used to study the bioactivity inhibition of PP1 by MCLR,MCLF,MCLA,MCLY and MCLW.The molecular toxicity test was combined the IC50 of MCs on PP1.The inhibited effect of MCs on the biological activity of PP1 as follows: MCLR?2.6 ?g/L?> MCLF?4.4 ?g/L?> MCLA?5.53 ?g/L?> MCLY?7.9 ?g/L?> MCLW?13.6 ?g/L?.MCs-PP1 was obtained by the MOE molecular docking.The docking simulation of MCs-PP1 was optimized.According to the cognition of PP1 on the interaction site of MCs,the activity of MCs inhibitory protein phosphatase PP1 can be changed from the energy changes,combined area,hydrogen bond,ionic bonds and so on.The results of molecular toxicity test and MOE molecular dock simulation results showed as follow.Adda5 residue combined area with PP1 was positively related with toxicant toxicity.The hydrogen bond of Leu2?Arg96,IsoAsp3?Arg96 and IsoAsp3?Tyr134 were negatively related with the toxicity of toxins,Z4?Glu275 were positively related with toxins' toxicity.The interaction between Mn²⁺-His173,Mn²⁺-Asn124 and Mn²⁺-Asp92 ion bonds were posstively related with the toxicity of toxins.?2?Study on the difference mechanism of microcystin-LR disinfection by-product inhibited the biological activity of PP1.In this study,MCLR was used as the basic research object for the study of microcystin disinfection by-products by traditional chlorine disinfection.Combined with molecular toxicity evaluation and molecular dock simulation,and its bio-toxicity effect of a comprehensive evaluation and regulation.The IC50 of MCLR-DBPs were obtained by toxicity test.The inhibitory effect of microcystin and its disinfection by-products on the biological activity of PP1 as follows: MCLR?2.6 ?g/L?> P3?21.3 ?g/L?> P1?32.7 ?g/L?> P4?73.8 ?g/L?>P2?113.7 ?g/L?>P5.Finally,the MCLR-DBPs and PP1 conjugates were obtained by the modification of MCLR-PP1 by MOE molecular simulation,and the energy of MCLR-DBPs and PP1 were optimized respectively.From the energy change,the combined area,hydrogen bond and ionic bond on the biological mechanism of MCLR-DBPs protein phosphatase 1 were analyzed deeply.The results of molecular toxicity test and MOE molecular dock simulation results showed as follow.The total binding area of ligand,Adda5 residue and the whole energy of MCs/MCLR-DBPs on PP1 were positivelyrelated with toxicant toxicity.Leu2?Arg96 was positively related with the toxins' toxicity,and Mdha7?Glu275,Iso Asp3?Arg96,Mdha7?Gly274,Adda5?Arg221,Glu6?His125 were negatively related with the toxicity of toxins.The covalent bond force of Asn278-Cys273 was negatively with the inhibitory of toxin on the bio-activity of PP1.The interaction between Mn²⁺-His173?Mn²⁺-His248?Mn²⁺-Asp64 ion bonds and the interaction of the whole Mn²⁺ ion bonds were positivelyrelated with the bio-toxicity of PP1.?3?Study on the difference mechanism of microbial activity of inhibited of PP1 by microcystin and MC-GSHs.MC-GSHs transformation pathway was regulated by the combination of MS,MS/MS,molecular toxicity evaluation and molecular dock simulation.MCs/MC-GSHs inhibited PP1 biological activity by molecular mechanism.The inhibitory effect of MCs/MC-GSHs on the biological activity of PP1 as follows: MCLR?2.6 ?g/L?> MCRR?23.3 ?g/L?> MCLR-GSH?83.4 ?g/L?> MCRR-GSH?95.1 ?g/L?.The MCs/MC-GSHs inhibited PP1 were detailed analyzed from the energy change,combined area,hydrogen bond,ionic bond and so on.The results of molecular toxicity test and MOE molecular dock simulation results showed as follow.Adda5 residue combined area with PP1 was positivelyrelated with toxicant toxicity.The combined area of MC-GSHs-PP1/H2 O,the hydrogen bond of X2?Arg96,Glu6?Tyr272,Arg4?Glu275,Mdha7-GSH?Asn278 and Mdha7-GSH?Asn271 were positively related with the toxicity of toxins,Adda5?Arg221 was positively related.The covalent bond of Mdha7-Cys273 was an important parameter for the inhibitory effective of MC-GSHs.The interaction between Mn²⁺-His173 and Mn²⁺-Asp92 ionic bonds were negatively related,and Mn²⁺-Asn124,Mn²⁺-His248,Mn²⁺-Asp64 and Mn²⁺-His66 ionic bonds were positively related with the toxicity of toxins.