Systematic Analysis Of Protein N-terminal Modification Spectrum Based On Proteomic Technique In Escherichia Coli

Escherichia coli is the host of exogenous gene expression.Considering its simple genetic background,E.coli is often used as a model organism for the study of prokaryotic microorganisms.In recent years,with the acid of technology,advancing of proteomics based on macromolecular mass spectrometry is excieting,a large number of studies on protein expression profiles and post-translational modification profiles in Escherichia coli have been reported,including the effects of environmental stimuli on protein stability and post-translational modification of proteins(non-N-terminal),nonetheless rare revisions have systematically analyzed the original N-terminal and post-translational modification of proteins in E.coli.In this study,TAILS was used to enrich and quantitatively analyze E.coli for the first time.The N-terminal status of E.coli protein in different nutritional environments was studied.The large-scale identification and analysis of protein N-terminal by proteomics will help to study the function of N-terminal and N-terminal modified animal and plant cells more deeply and systematically.In this subject,TAILS technology was firstly used to enrich the N-terminal of E.coli protein under different sugar concentration.SILAC technology was used firstly to analyze the N-terminal modification types and analyze systematically amino acid sequence characteristics of E.coli protein.The results showed that 105 N-terminal peptide fragments of acetylated proteins were recognized,besides the N-terminal acetylation of proteins in E.coli speedly increased under high glucose induction.A new-fangled substrate of N-terminal acetyltransferase(Rim I)was found in E.coli,which was verified by in vitro enzymatic experiments.The unprecedented application of TAILS technology in E.coli protein N-terminal enrichment has increased the enrichment types,which further helped us to determine the primary structure and variants,verify the types of post-translational modifications of E.coli proteins,TAILS has many advantages of high efficiency,high throughput,unbiased and systematics over the traditional biological methods.Besides,it makes appearance of new types of modifications possible.It provides a guarantee for further revealing the reasonable mechanism of N-terminal proteins regulation at the molecular level in bacterial life activities.