Side chain modification

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The side chain modification includes post-translational modifications of the side chains of amino acids in proteins . In contrast to the side chain modification, the terminal (terminal) modification refers to the modification of the N - or C -terminus .

properties

The post-translational modification of the side chains creates various modified amino acids in a protein. Among other things, the side chains of lysine are acetylated , arginine and lysine methylated , glutamic acid carboxylated , proline hydroxylated or serine , threonine and tyrosine phosphorylated . Glycosylations and some lipid modifications are also side chain modifications. The side chain modifications increase with age.

Applications

While most side chain modifications are generated enzymatically, some modifications of the side chains of proteins also arise in the course of glycation with carbohydrates or through oxidation (e.g. cysteine to cysteine ​​sulfonic acid or carbonyls ). When cooking with dry heat, the Maillard reaction produces melanoidins , which contain side chain modifications with reducing sugars .

In biochemistry, hydroxylations are used to label proteins for mass spectrometry . During radioiodination , tyrosine side chains are oxidized and labeled with radioactive iodine . During a deuteration , both terminal hydrogen atoms and those on side chains are exchanged for deuterium .

Individual evidence

  1. ↑ Donald Voet, Judith G. Voet, Charlotte W. Pratt: Fundamentals of Biochemistry: Life at the Molecular Level . Wiley, 2006. ISBN 978-0-47121495-3 . P. 89.
  2. ^ AJ Bailey: Molecular mechanisms of aging in connective tissues. In: Mechanisms of aging and development. Vol. 122, Number 7, May 2001, pp. 735-755, PMID 11322995 .
  3. ↑ KI Piatkov, CS Brower, A. Varshavsky : The N-end rule pathway counteracts cell death by destroying proapoptotic protein fragments. In: Proc Natl Acad Sci USA (2012), Volume 109 (27), pp. E1839-47. doi : 10.1073 / pnas.1207786109 . PMID 22670058 ; PMC 3390858 (free full text).
  4. ^ PA Grimsrud, H. Xie, TJ Griffin, DA Bernlohr: Oxidative stress and covalent modification of protein with bioactive aldehydes. In: The Journal of biological chemistry. Volume 283, number 32, August 2008, pp. 21837-21841, doi : 10.1074 / jbc.R700019200 , PMID 18445586 , PMC 2494933 (free full text).
  5. ↑ K. Takamoto, MR Chance: Radiolytic protein footprinting with mass spectrometry to probe the structure of macromolecular complexes. In: Annual review of biophysics and biomolecular structure. Volume 35, 2006, pp. 251-276, doi : 10.1146 / annurev.biophys.35.040405.102050 , PMID 16689636 .