Yeom, Jeonghun Ju, Shinyeong Choi, YunJin Paek, Eunok Lee, Cheolju 2024-01-20T01:02:18Z 2024-01-20T01:02:18Z 2021-09-05 2017-07-26 2045-2322 https://pubs.kist.re.kr/handle/201004/122506 Various forms of protein (proteoforms) are generated by genetic variations, alternative splicing, alternative translation initiation, co- or post-translational modification and proteolysis. Different proteoforms are in part discovered by characterizing their N-terminal sequences. Here, we introduce an N-terminal-peptide-enrichment method, Nrich. Filter-aided negative selection formed the basis for the use of two N-blocking reagents and two endoproteases in this method. We identified 6,525 acetylated (or partially acetylated) and 6,570 free protein N-termini arising from 5,727 proteins in HEK293T human cells. The protein N-termini included translation initiation sites annotated in the UniProtKB database, putative alternative translational initiation sites, and N-terminal sites exposed after signal/transit/propeptide removal or unknown processing, revealing various proteoforms in cells. In addition, 46 novel protein N-termini were identified in 5' untranslated region (UTR) sequence with pseudo start codons. Our data showing the observation of N-terminal sequences of mature proteins constitutes a useful resource that may provide information for a better understanding of various proteoforms in cells. English NATURE PUBLISHING GROUP ALTERNATIVE TRANSLATION INITIATION MS-GF PLUS DATABASE PROTEOMICS PEPTIDES ACETYLTRANSFERASES IDENTIFICATION SEARCH ACETYLATION INSIGHTS Comprehensive analysis of human protein N-termini enables assessment of various protein forms Article 10.1038/s41598-017-06314-9 1 SCIENTIFIC REPORTS, v.7 SCIENTIFIC REPORTS 7 scie scopus 000406366400007 2-s2.0-85026416796 Multidisciplinary Sciences Science & Technology - Other Topics Article ALTERNATIVE TRANSLATION INITIATION MS-GF PLUS DATABASE PROTEOMICS PEPTIDES ACETYLTRANSFERASES IDENTIFICATION SEARCH ACETYLATION INSIGHTS