Post-translational modifications Poly

Fig. 6. Post-translational modifications of core and linker histones. The sites of acetylation, phosphorylation, poly-ADP ribosylation, methylation, and ubiquitination are incficated by numbers that correspond to the amino acid position from the N-termini of the molecules. The nomenclature of histone HI variants is as in Fig. 3. The length of C- and N-terminal tails is in relative scale between core histones to illustrate primary structural differences between these proteins.

Lindahl, T., Satoh, M.S., Poirier, G.G. and Klungland, A. (1995) Post-translational modification of poly(ADP-ribose) polymerase induced by DNA strand breaks. Trends Biochem. Sci., 20, 405—411. 

R. N. Reusch, O. Shabalin, A. Crumbaugh, R. Wagner, O. Schroder and R. Wurm (2002). Post-translational modification of E. coli histone-like protein H-NS and bovine histones by short-chain poly-(R)-3-hydroxybutyrate (cPHB). FEBS Lett., 527, 319-322. 

NAD is used in post translational modification of a variety of proteins, nc>tab y some of the proteins of the chromosomes. The chromosomes are composed of DNA, histones, and nonhistone proteins. The histones, which are distinguished by their high content of basic amino acids, serve as a scaffold and maintain the coiled and folded structure of the DNA. The other proteins are used in regulating the expression of specific genes. Poly(ADP-ribose) polymerase catalyzes the attachment of ADP-rlbose to various chromostimal pniteins. This modification, shown in Figure 9.65A, is more dramatic than a simple methylalion or phosphorj lation. The enzyme uses NAD as a substrate. Here, NAD docs not serve its usual role as an Oxidant or reductant. The ADP-ribosyl moiety of NAD is donated to the acceptor protein. A molecule of nicotinamide is discharged with each event of... 

Tliis method enables the rapid identification of DNA-binding proteins. Immobifized DNA probes haiboring a specific sequence motif ai e incubated with cell or nuclear extract. Proteins are analyzed directly off the solid support by MALDI-TOF. Tlie determined mo-leculai masses aie often sufficient for identification. If not, the proteins ai e subject to MS peptide mapping followed by database seaiches. Apai t from protein identification, the protocol also yields information on post-translational modifications. Tlie protocol was validated by the identification of known prokaiyotic and eukai yotic DNA-binding proteins, and is use provided evidence that poly(ADP-ribose) polymerase exhibits DNA sequence-specific binding to DNA. ... 

Early in our studies it was expected that the post-translational modification of proline hydroxylation, so important to proper collagen structure and function, would raise the value of the temperature, T, for the onset of the inverse temperature transition for models of elastin. Accordingly, hydroxyproline (Hyp) was incorporated by chemical synthesis into the basic repeating sequence to give the protein-based polymers poly[fvs,i(Val-Pro-Gly-Val-Gly), fHyp( al-Hyp-Gly-Val-Gly)], where f sl -i- fnyp = 1 and values of fnyp were 0, 0.01, and 0.1. The effect of prolyl hydroxylation is shown in Figure 7.49. Replacement of proline by hydroxyproline markedly raises the temperature for hydrophobic association. Prolyl hydroxylation moves the movable cusp of... 

Malik N, Smulson M (1984) A relationship between nuclear poly (adenosine diphosphate ribosylation) and acetylation post-translational modifications I. Nucleosome Studies Biochemistry 23 3721-3725... 

Ribosomal protein S6 from Escherichia coli undergoes a unique post-translation modification where up to six glutamic acid residues are ligated to the C-terminus. [82-84] RimK, also a member of carboxylate-amine/thiol Ugase superfamily, mediated this post-translahonal modification. [84] In vitro analysis of RimK s)rnthesis resulted in 46-mer (maximum length) of a-poly (L-Glu) at pH 9.0, 30 °C. The maximum chain length was pH dependent. Furthermore, RimK demonstrated strict substrate specificity for Glu. [72]... 

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