title: Isolation of acetylated and free N-terminal peptides from proteomic samples based on tresyl-functionalized microspheres.
abstract: Analysis of protein N-termini is of great importance in helping to figure out important posttranslational modifications (PTMs) occurred in N-termini. Those PTMs include initial methionine removal, proteolytic cleavage, peptide signal processing, or N-terminal acetylation, which are usually neglected by conventional shotgun proteomics strategies. Herein, we develop a protein N-terminal peptides enrichment method based on commercial tresyl-functionalized microspheres (TFM). TFM could specifically immobilize the non-N-terminal peptides (internal peptides) from the supernatant. We demonstrated the isolation by TFM was more fast and efficient than formyl or epoxy-functionalized microspheres. Furthermore, this method could simultaneously isolate not only naturally free but acetylated blocked N-terminus. That facilitates a more comprehensive acquisition of N-terminus. After being verified by three standard proteins, cytochrome C, ribonuclease B and bovine serum albumin, this method was applied to mouse liver protein sample. We identified 122 naturally acetylated N-terminus and 107 free N-terminus in the sample. With the good performance of TFM, this method is efficient and useful for N-termini recovery.
authors.affiliation: Department of Chemistry and Institute of Biomedical Sciences, Fudan University, Shanghai 200433, China.
authors.forename: Lanting
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Chemistry and Institute of Biomedical Sciences, Fudan University, Shanghai 200433, China.
authors.forename: Guoquan
authors.initials: G
authors.lastname: Yan
authors.affiliation: Department of Chemistry and Institute of Biomedical Sciences, Fudan University, Shanghai 200433, China. Electronic address: xmzhang@fudan.edu.cn.
authors.forename: Xiangmin
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000107:Acetylation; D000588:Amines / Q000737:chemistry; D000818:Animals; D002417:Cattle; D005591:Chemical Fractionation / Q000379:methods*; D008099:Liver / Q000737:chemistry; D008745:Methylation; D051379:Mice; D008863:Microspheres; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification*; D040901:Proteomics; D013450:Sulfones / Q000737:chemistry*
chemical_list: D000588:Amines; D010455:Peptides; D013450:Sulfones; C032605:2,2,2-trifluoroethanesulfonyl chloride
keywords: Acetylation; N-terminal peptides; Positional proteomics; Post translational modification; Tresyl