10 research outputs found
Study on the Analysis of Post-Translational Modification in Protein by Mass Spectrometry
A tandem time-of-flight mass spectrometer was built for photodissociation of singly protonated peptides and small proteins generated by matrix-assisted laser desorption ionization. Photodissociation was done in a second source after deceleration of precursor ions. The delayed extraction/post-acceleration scheme was used for the product ions. For the photodissociation at 193 nm of small singly protonated peptides, the present instrument showed much better sensitivity and resolution for product ions than the previous one, even though the overall spectral patterns obtained with the two instruments were similar. The present instrument was inferior in precursor ion selection and background noise level. Photodissociation was achieved for precursor ions as large as the singly protonated ubiquitin (m/z 8560.63), indicating that the photoexcitation is capable of supplying a sufficient amount of internal energy to dissociate large singly protonated proteins. As the precursor ion m/z increased, however, product ion signals deteriorated rather rapidly. As in the photodissociation of small peptide ions with m/z around 1000, the types of the product ions generated from singly protonated peptides with m/z in the range 2000-4000 were mostly determined by the positions of arginine residues. Namely, an and dn ions dominated when an arginine residue(s) was near the N-terminus while vn, wn, xn and yn dominated when the same residue(s) was near the C-terminus. In addition, dn, vn and wn ions were generated according to the correlation rules previously observed in the collisionally activated dissociation. Isoleucine and leucine isomers could be easily distinguished based on the wn and dn ions.
A time-of-flight mass spectrometer equipped with two reflectrons was constructed for multiplexed photodissociation tandem mass spectrometry of peptide ions generated by matrix-assisted laser desorption ionization. A linear reflectron was used for high resolution selection of a precursor ion while a quadratic reflectron was used for product ion analysis. By photoexciting a precursor ion inside a cell floated at high voltage, information (MS3) on intermediate ions generating a particular product ion was obtained. Fully multiplexed detection resulted in good MS3 signal levels. Use of the quadratic reflectron allowed intermediate ion mass determination within 4 Da.
Post-translational modification is the chemical modification of a protein. After translation, the post-translational modification of amino acids changing the structure and functions of protein by attaching to them other biochemical functional groups such as phosphate, sulfate, carbohydrates. In various post-translational modifications, phosphorylation and nitration of protein were investigated.
For tryptic phosphopeptide analysis, we used photodissociation (PD) multi-stage (MSn) time-of-flight mass spectrometry that can monitor reaction intermediates with lifetime as short as 100 nsec to study the formation of dephosphorylated sequence ions such as yn β H3PO4. yn β H3PO4 was found to be formed mainly by H3PO4 loss from yn. Even when yn was absent in PD-MS2 spectrum, its m/z could be predicted from those of yn β H3PO4. Complete sequence coverage was possible when the data from PD-MS2 and PD-MS3 were combined, demonstrating the utility of transient ion detection by PD-MS3 for structure analysis.
In ultraviolet photodissociation of phosphopeptide ions with a basic residue (arginine, lysine, or histidine) at the N-terminus, intense an β 97 peaks were observed. These ions were formed by cleavage at phosphorylated residues only. For multiply phosphorylated peptides, this site-specific cleavage occurred at every phosphorylated residue. H/D exchange studies showed that an β 97 was formed by H3PO4 loss from an + 1 radical cations.
Nitration of tyrosine residues in proteins is an important post-translational modification related to various diseases such as Alzheimers. In this work, efficient and selective photodissociation (PD) at 355 nm was observed for [M + H]+, [M + H β 16]+, and [M + H β 32]+ generated by matrix-assisted ultraviolet laser desorption ionization (UV-MALDI) of tyrosine-nitrated peptides (nitropeptides). Product ion spectra obtained by post-source PD at this wavelength contained useful information on amino acid sequence. The spectra for nitropeptides obtained with 355 nm irradiation inside the ion source (MALDI/in-source PD) displayed characteristic triplet patterns due to PD of the above ions. For peptides displaying prominent signal in MALDI mass map of a tryptic mixture, which are mostly those with arginine at the C-terminus, in-source PD allowed positive identification of their tyrosine-nitrated forms. Identification of such nitropeptides was possible at the 10 fmol level in tryptic digest of 100 fmol BSA.맀νΈλ¦μ€ 보쑰 λ μ΄μ νμ°© μ΄μ¨νμ μν΄ μμ±λ ν©νμ΄λ μ΄μ¨ λ° μ§λμ΄ μμ λ¨λ°±μ§ μ΄μ¨μ κ΄λΆν΄λ₯Ό μν΄ μ΄ λ¨κ³ μ§λλΆμκΈ°λ₯Ό μ μνμλ€. μ΄μ¨μ κ°μ ν λ λ²μ§Έ μ΄μ¨μμμ κ΄λΆν΄λ₯Ό νμλ€. ν©νμ΄λ μ΄μ¨μ 193 νμ₯ κ΄λΆν΄ μ€ννΈλΌμ κΈ°μ‘΄μ μ μλ μ§λλΆμκΈ°μ κ±°μ κ°μ κ²½ν₯μ 보μμΌλ λ μ’μ κ°λμ λΆλ³λ₯μ 보μλ€. νμ§λ§ μ νμ λμμμ κ΄λΆν΄λ₯Ό ν μ μμκ³ μ‘μμ΄ λ§μλ€. λ¨λ°±μ§ μ΄μ¨μ΄ λΆν΄λκΈ° μν μΆ©λΆν λ΄λΆμλμ§λ₯Ό λ μ΄μ κ° κ³΅κΈν μ μλμ§λ₯Ό νμΈνκΈ° μν΄ μ λΉν΄ν΄ μ΄μ¨μ κ΄λΆν΄λ₯Ό μ€μνμκ³ κ΄λΆν΄λ₯Ό ν μ μμλ€. νμ§λ§ μ§λμ΄ μ»€μ§λ©΄μ μμ± μ΄μ¨μ μ νΈκ° κΈκ²©νκ² κ°μνμλ€. μ§λ λ μ νλΉκ° 1000 μΈ ν©νμ΄λ μ΄μ¨μ κ΄λΆν΄ μ€ννΈλΌμ²λΌ μ§λ λ μ νλΉκ° 2000-4000 μΈ ν©νμ΄λ μ΄μ¨μ κ΄λΆν΄ μ€ννΈλΌλ μλ₯΄κΈ°λμ μμΉμ λ°λΌ μμ±λ μ΄μ¨μ΄ κ²°μ λμλ€.
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리νλ νΈλ‘ μ μ¬μ©νμλ€. κ³ μ μμ΄ μ μ©λ μ
λ΄λΆμμμ κ΄λΆν΄λ‘ μ΅μ’
μμ±μ΄μ¨μ μ€κ° μ΄μ¨λ€μ μ§λμ νμΈνμλ€. μ΄λ μΌ λ¨κ³ μ§λλΆμ μ€ννΈλΌμ νλμ΄λ€. 4 Da λ΄μ μ€μ°¨λ‘ λͺ¨λ μμ± μ΄μ¨μ μ€κ° μ΄μ¨μ ν λ²μ μμ λΌ μ μμλ€.
λ²μ ν μμμ λ¨λ°±μ§μ ννμ λ³νμ΄λ€. μλ―Έλ
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μΌκΈ°λκ° ν° μλ―Έλ
Έμ°μΈ μλ₯΄κΈ°λ, νμ€ν°λ, λΌμ΄μ μλ―Έλ
Έμ°μ΄ ν©νμ΄λμ N λ§λ¨μ μλ μΈμ°ν ν©νμ΄λμ κ΄λΆν΄ μ€ννΈλΌμμ νΉμ§μ μΈ μ΄μ¨μ΄ κ²μΆλμλ€. μ΄ μ΄μ¨μ μΈμ°νκ° λ μλ―Έλ
Έμ°μ΄ μλ μμΉμμλ§ μμ±λμ΄ λμ€λ κ²μΌλ‘, μ΄ μ΄μ¨μ΄ κ²μΆλλ μμΉλ§μΌλ‘ μΈμ°ν μ리λ₯Ό κ²°μ ν μ μμλ€.
λ¨λ°±μ§ λ΄ νμ΄λ‘μ μ λμ΄νΈλ‘νλ μμΈ νμ΄λ¨Έ λ³κ³Ό κ΄λ ¨λ μ€μνλ¨λ°±μ§ λ²μ ν μμμ΄λ€. 355 νμ₯μ λ μ΄μ λ₯Ό μ΄μ©νμ¬ ν¨κ³Όμ μ΄κ³ μ νμ μΌλ‘ λμ΄νΈλ‘ν ν©νμ΄λλ₯Ό κ΄λΆν΄ ν μ μμλ€. μ΄μ¨μ μΈ κ΄λΆν΄ μ€ννΈλΌμ λμ΄νΈλ‘ν ν©νμ΄λμ μμ κ²°μ μ νλλ° λμμ΄ λλ λ°©λ²μ΄μλ€. νΈλ¦½μ μ μν΄ λ§λ€μ΄μ§ ν©νμ΄λ νΌν©λ¬Όμ λμ΄νΈλ‘ν ν©νμ΄λλ₯Ό λ£μ ν 맀νΈλ¦μ€ 보쑰 λ μ΄μ νμ°© μ΄μ¨νλ‘ μ΄μ¨μ λ§λ€μ΄ μ΄μ¨μ λ΄μμ 355 λ μ΄μ λ‘ κ΄λΆν΄ νμλ€. λμ΄νΈλ‘ν ν©νμ΄λλ§μ μ νμ μΌλ‘ κ΄λΆν΄ ν μ μμκ³ μ΄λ‘μ¨ μ½κ² λμ΄νΈλ‘ν ν©νμ΄λλ§μ μ°Ύμ μ μμλ€.Docto
Electromanipulation of mammalian cells in microchip
Thesis (master`s)--μμΈλνκ΅ λνμ :κΈ°κ³ν곡곡νλΆ,2004.Maste