Two new proteins from physcomitrella patens were sequenced by nanoLC-FT-ICR tandem mass spectrometry.Eight and seven peptides were sequenced for spot 303 and spot 413 respectively.Database search was performed through the search engine Mascot (www.matrixscience.com) by MS/MS ion search program and Sequence Tag program.Blast was performed too.No statistical significant results were obtained from database search.The reliable amino acid sequences can be used for gene clone due to high mass accuracy.This research indicates that nanoLC-FT-ICR tandem mass spectrometric technique is powerful tools for new protein sequence analysis and will play an important role in plant proteomics research.
This paper reported the identification of the primary structure of two peptides using nanoelectrospray tandem mass spectrometry(Nano-ESI MS/MS).Firstly,the relative molecular mass of two peptides were determined in ESI-TOF MS mode.Then fragmentation ions were obtained by selecting [M+2H]2+ ion using tandem mass spectrometry(MS/MS).Finally,the primary structure of triptorelin is determined to be E’HWSYWLRPG’,of which the N-terminal is pyroglutamic acid (E’) and the C-termianl is glycinamide (G’).The primary structure of unknown peptide was identified to be T’VSP VWLPPSVY by sequence docking method,of which the N-terminal occurs threonine phosphorylation (T’) and the foruth proline is added with sodium ion (P).The data suggested that electrospray Tandem mass spectrometry technique have obvious advantage in analyzing the full sequence of modified or unknown peptides.
C-terminal sequence is important for the function of a protein.C-terminal sequencing is necessary for structure identification of recombinant drugs.In this paper,a new method based on CNBr cleavage coupled with ESI MS/MS was established and successfully applied to C-terminal sequence analysis of recombinant human TNFR and neuregulin.Results showed,C-terminal sequences with 19 and 11 amino acids were identified respectively.This new method was sensitive,reproducible and useful for C-terminal sequence analysis of recombinant proteins.
Neuregulin plays an important role in heart structure and function.Research discovered that recombinant neuregulin could reduce the degree of damage on myocardial cells caused by ischemia,hypoxia and viral infection.The primary structure,including N-terminal sequence,C-terminal sequence,PMF,accurate molecular mass,and disulfide bonding pattern of recombinant human neuregulin,have been identified by ESI-Q-TOF MS,Autoflex MALDI-TOF MS,9.4T Apex Q-FT MS and Ultraflex Ⅲ MALDI-TOF/TOF combining with two e]ymatic digestion.A abnormal peptide impurity in this drug was found and sequenced by Q-TOF MS and TOF/TOF MS,this is useful for the product quanlity control.
