Study On The Influences Of Amino Acids Characteristics On Protein Folding Rate And The Base Match Between Introns

Protein plays an important role in all life activities,including metabolism,growth and so on.In recent years,the folding rate of protein has become one of the hot topic in molecular biology.And most of the research focuses on the environment of protein,protein structure,and so on.And then,protein structure can be predicted by amino acid sequence,so the effect of amino acid sequences on protein folding rate can't be ignored.Previously,the effects of amino acid sequences on the protein folding rate were explored by various theoretical approaches.In this work,the effect of amino acid sequence on protein folding rate based on the classification of amino acids.In addition,some researches demonstrated that non-coding sequence plays an important role in life activities.And the formation and characteristic of circRNA have become a new hot topic.CircRNA is a new type of non-coding RNA that is formed by special alternative splicing by introns or introns and exons.The related results indicated that circRNA have great potential for regulating gene transcription,growth,and disease prediction.In this work,firstly,the effect of the relative amino acid usage of different amino acids on protein folding rate was studied,and then the correlation between introns in the same RNA sequence was analized with local alignment method,and tried to explore the mechanism of the circular-forming of circRNAs was discussed.The main contributions are summarized as follows:1.According to the classification of amino acids,a parameter that describes the information of amino acid sequence was defined,which was Relative Amino Acid Usage(RAAU).Based on the related databases and researches,a protein folding database was founded,in which contains the information of relative amino acid usage and protein folding rate of rach protein.2.Using all proteins of in our data,the correlation between protein folding rate ln(k_f)and relative amino acid usage(RAAU)was statistically analyzed.The results showed that the relative usage of different amino acids had significant difference influences on the protein folding rate.Among of these,the relative usage of strong hydrophilic amino acid and the amino acid of proline and glycine has a good correlation with protein folding rate.3.Proteins can be divided into two-state protein and multi-state protein,and then for each type of protein can be used as the research object,and relative amino acid usage have effect on the rate of protein folding the linear relationship was analyzed.For the different folding protein,the results indicated that the influence of the usage of the same amino acid varies greatly on the folding rate of different kinds of proteins.4.The human ribosomal protein genes were selected as the research sample,All intron sequences in each protein pre-RNA were extracted.On this basis,the length distribution characteristics of the first intron were statisticed,the result shown that the length of the first intron is mostly around 80bp~240bp.5.Except the first intron,the other intron sequences were transformed into their complementary sequences,and then the matching characteristics of these intron sequences were analyzed with the local similarity alignment software,the length of the optimal matching segment and its distribution of GC content.The results show that the optimal matching segment length was about 15bp,and the GC content of the optimal matching segment appeared at 0.62 and 0.41 respectively.6.Based on the optimal matching segment,the relative location distribution of the optimal matching segment of the first intron sequence were statisticed,and the first intron sequence fragments were divided into high GC group and low GC group according to GC content.And the relative location distribution of the first intron optimal matching fragment in two groups of introns were ststisticed.The result demonstrated that the optimal matching fragment location was normal distribution for the overall first intron sequence,and the optimal matching fragment was at 50-70bp.For the high GC group,the optimal matching fragment was at 60-70bp,but there were multimodal state for the low GC group.