Investigations Of The Interaction Between Small Molecule Compounds And Human Serum Albumin By Spectroscopic And Molecular Modeling Methods

Serum albumin is the most abundant protein in the blood and has many important physiological functions.It is primarily responsible for maintaining the pH and osmotic blood pressure of the blood,and the physiological role of serum albumin involves binding,transporting,and delivering many ligands in the blood to its target organs.After the serum albumin is combined with a small molecule compound,it plays a role of storage and transport.Studying the binding constants,binding sites,binding forces,binding distances,and conformational changes of small molecule compounds and HSA at the molecular level helps to clarify the characteristics of small molecule compounds in vivo after binding to serum albumin,Such as absorption,distribution,transmission,metabolism,excretion,stability and toxicity.In addition,the conformation of serum albumin will change after binding to small molecule compounds,and this change will affect the secondary and tertiary structure of albumin and its carrier protein and its biological function.Studying the mechanism and law of action between natural small molecule compounds and serum albumin can provide theoretical basis for future clinical use and further research.This subject first studied the interaction between arbutin and human serum albumin by using multispectral method combined with molecular docking technology,and then the main active ingredient of atractylolide,atractylolide I,II,III,and human serum albumin were studied.1.Study on the interaction between arbutin and human serum albuminArbutin,also known as arbutin,has an anti-inflammatory and bactericidal effect,and can be used in asthma treatment to extend the incubation period and play a role in asthma.In order to simulate the interaction between small molecule drugs and human serum albumin after absorption into the blood,this experiment used multispectral technology and molecular docking technology to study the interaction between arbutin and human serum albumin under sugarless and normal human blood glucose conditions,respectively.By comparing the difference in the interaction between arbutin and human serum albumin in two environments,the effect of normal human blood glucose environment on the interaction between arbutin and human serum albumin was explored.The results showed that:under sugarless conditions,the addition of arbutin reduced the fluorescence intensity of human serum albumin and the phenomenon of fluorescence quenching occured.K_q was greater than 2.0×10¹⁰L/?mol·s?,The type of HSA quenching was static quenching;the binding constant Ka value decreased with increasing temperature;the number of binding sites was approximately 1;hydrogen bonds and van der Waals forces played a major role in their binding process;the binding sites of the two were sites Site I;both three-dimensional fluorescence and circular dichroism spectroscopy indicated that the conformation of HSA had changed after arbutin action.Compared with non-sugar conditions,the conformation of HSA under sugar environment was changed,which affected the interaction between arbutin and HSA.It also increased the binding constant and the binding force of arbutin and HSA.The results of the molecular docking also confirmed the above experimental results.Through a comparative study of the interaction between arbutin and human serum albumin in a sugar-free environment and a normal human blood glucose environment,the influence of human normal blood glucose environment on the interaction between small molecule compounds and human serum albumin was discussed,which has certain guided significance for the subsequent research on the interaction between small molecule compounds and human serum albumin.2.Study on the Interaction between Atractylenolide?,?,?and Human Serum AlbuminAtractylenolide I,II,III are the main active ingredients and characteristic ingredients of Atractylodes.Studies have shown that atractylodes can significantly inhibit the production of inflammatory mediators and inflammatory factors.In addition,it has anti-rotavirus?RV?effect in vitro and in vivo.Under the simulated physiological environment of the human body,the interaction between atractylolide I,II,III and human serum albumin was studied through multispectral technology combined with the simulation of molecular docking.It was found that the quenching of HSA fluorescence by atractylolide I,II,and III were all static quenching.;The forces at the time of interaction were hydrogen bonds and van der Waals forces;And they all binded to the HSA site I site?subdomain IIA?;The experimental results of the circular dichroism spectrum and the three-dimensional fluorescence spectrum fully showed that the addition of atractylolide I,II,and III had changed the spatial conformation of HSA.Molecular docking simulations also confirmed that atractylodes lactones I,II,and III are mainly bound to HSA's site I site by hydrogen bonding and van der Waals forces.Through the calculation of the binding constant,it was found that the atractylolide III was the largest,followed by the atractylolide I,and the atractylolide II was the smallest.The results of this experiment can be analyzed by combining the molecular structure.Atractylolide III had one more hydroxyl group than atractylolide II,and the hydrogen bond made the binding force greater;Atractylolide I had one more double bond and conjugated double bond than that of atractylolide II.The planar structure made it easier to integrate with HSA.In this experiment,by explaining the differences in the binding properties of small molecular compounds with similar structure to human serum albumin at the molecular level,it was possible to predict the interaction of other structurally similar drugs with human serum albumin and to understand its transport and metabolism in the body.Which will provide guidance for drug molecular design.