Catassembly Of Nucleic Acids With Complex Structures

Creating new material is one of the ultimate goals of chemists,and many materials based on molecules are molecule assemblies,which are connected by non-covalent interactions.Molecule assembly can be divided into self-assembly and assisted-assembly.Among the many kinds of assisted-assembly,there is a special kind called catassembly,which means catalyzed-assembly.If one substance is added to the assembly system and can accelerate the assembly process,this substance is called catassembler,and this process is called catassembly.Catassembler for catassembly is like catalyst for catalysis.Many assembly phenomena in biology and macromolecule assembly are catassembly cases.However,in small molecule assembly which many chemists are working on,there are few cases of catassembly now.What's the difference between biological assembly and small molecule assembly?How can we set up and improve catassembly systems?How to control assembly and improve its function?There are lots of questions to answer.In this thesis,we try to understand assembly from the angle of simplicity and complexity.In simple system,subunits can assemble directly,but in complex system assembly need the help from environment and other molecules,especially catassembler.We use the idea of biomimetic,to set up catassembly system with complex structured DNA and RNA.We prove that DNA and RNA with complex structure also meet the problem of misfolding.DNA/RNA can play the role of molecular chaperone,which are catassembler for folding of DNA and RNA.The accomplishments can be summarized as follows:(1)In chapter 2,we divide assembly into simple assembly and complex assembly,and analyze their differences.We discuss the pros and cons of complex assembly,and how the system reacts to complexity.In complex assembly system,the assembly process need to be assisted,especially the help of catassembler.The strategy to improve catassembly is also been discussed.(2)In chapter 3,a catassembly system of the conformation transform is established.Single strand nucleic acids with complex structure can fold into 2 different conformations,which can be controlled by adjusting annealing rates.We find that quick annealing leads to kinetic folding,and slow annealing leads to thermodynamic folding.The adding of catassembler strand can accelerate the transformation of kinetic conformation to thermodynamic conformation.(3)In chapter 4,we synthesized single strand DNA with kinetic conformation by enzyme ligation method.After getting of pure kinetic formation DNA,a catassembler sequence was added and the conformation transformation get accelerated.The kinetics of the catassembly process was studied.The study shows that nucleic can be molecular chaperone of nucleic acid.(4)In chapter 5,we used RNA polymerase to synthesize RNA with complex structure.PAGE and fluorescence data shows that RNA fold during transcription and it may lead to misfolding.Catassembler can help misfolded RNA transfer to right folding.We combined the catassembly system with RNA interface.Results shows that catassembly can enhance the RNAi effect of complex structured RNA.