tailieunhanh - Báo cáo khoa học: K8 and K12 are biotinylated in human histone H4

Folding of DNA into chromatin is mediated by binding to histones such as H4; association of DNA with histones is regulated by covalent histone modifications,. acetylation, methylation, sought to identifyamino-acid residues that are biotinylated in histone H4,and to determine whether acetylation and methylation of histones affect biotinylation. Synthetic peptides spanning fragments of human histone H4 were biotinylated enzymatically using biotinidase. Peptide-bound biotin was probed with strept-avidin–peroxidase | Eur. J. Biochem. 271 Uv u 2004 FEBS 2004 doi K8 and K12 are biotinylated in human histone H4 Gabriela Camporeale1 Elizabeth E. Shubert1 Gautam Sarath2 Ronald Cerny3 and Janos Zempleni1 4 Department of 1Nutrition and Health Sciences 2USDA-ARS and Department of Entomology 3Department of Chemistry and Departments of Biochemistry and Animal Science University of Nebraska at Lincoln Lincoln NE USA Folding of DNA into chromatin is mediated by binding to histones such as H4 association of DNA with histones is regulated by covalent histone modifications . acelylaiion. methylation and bio tinyat10 n. We sought to id en t i ly ami noacid residues that are biotinylated in histone H4 and to determine whether acetylation and methylation of histones affect biotinylation. Synthetic peptides spanning fragments of human histone H4 were biotinylated enzymatically using biotinidase. Peptide-bound biotin was probed with strept-avidin-peroxidase. Peptides based on the N-terminal sequence of histone H4 were effectively recognized by biotinidase as substrates for biotinylation in contrast peptides based on the C-terminal sequences were not biotinylated. Substitution of K5 or K12 with alanine or arginine decreased biotinylation suggesting that these lysines are targets for biotinylation K5 and K12 are also known targets for acetylation. Chemical acetylation or methylation of a given lysine decreased subsequent enzymatic biotinylation of neighboring lysines consistent with cross-talk among histone modifications. Substitution of a given lysine positive charge with glutamate negative charge abolished biotinylation of neighboring lysines providing evidence that the net charge of histones has a role in biotinylation. An antibody was generated that specifically recognized histone H4 biotinylated at K12. This antibody was used to detect biotinylated histone H4 in nuclear extracts from human cells. These studies suggest that K5 and K12 in histone H4 are targets