Study On The Effects Of Common Divalent Metal Ions On The Structural Stability Of Lysozyme And The Correlated Mechanism

Lysozyme was a kind of hydrolase. In nature, lysozyme can be found almost allegg white from birds and games, all tear, saliva, blood, snivel, urine, milk and tissuesof mammals. It’s a small molecular alkaline protein. For a long time, lysozyme wasthe better model system to study protein space structure, enzyme kinetics, and therelationship between the molecular evolution and molecular molecular immunity.From now on, lysozyme was widely used on food industry, medicine and Enzymeengineering. With the stable protein structure, hen egg white lysozyem becomes thetypical representative figure, and it is the important model.Magnesium chlorate could induce lysozyme aggregation under some conditions,but the detail mechanism has been poorly understood. In this study, we employedmolecular biological experiments and molecular dynamic simulations to investigatethe aggregated property and structural stability of chicken lysozyme when treatedwith MgCl₂、CaCl₂、ZnCl₂、CuCl₂. The molecular biological results indicated that200mmol/L MgCl₂could obviously promote lysozyme to form dimer and trimer, Andwith the growth of the incubation time, the aggregates become increasingly evident;CaCl₂is more and more obvious with the increasing concentration of aggregation, butnot with the time growth aggregates obvious increase; ZnCl₂is more obvious on thelysozyme aggregation, growth gathered over time is also evident CuCl₂the effectnotas good as the above three kinds of salt. The simulation results indicated that200mmol/L MgCl₂、CaCl₂、ZnCl₂、CuCl₂. could induce large displacement of helix3andhelix4and weaken the disulfide bond Cys76-Cys94located in the aggregationcritical region （residue40to110）. In addition, our results suggested that the stabilityof hydrophobic core could be weakened by the decrease of hydrogen bonds numberin this region. But CuCl₂changes little. The impact of the lysozyme inhibitory effectZnCl₂> MgCl₂> CuCl₂> CaCl₂。On this way, we can find a better biology model toefficient application on food, health and desease.