Histone H4 (1-23)-GSGSK(Biotin)

Product Name: Histone H4 (1-23)-GSGSK(Biotin)

Sequence One Letter Code: SGRGKGGKGLGKGGAKRHRKVLR-GSGSK(Biotin)

Sequence Three Letter Code: H-Ser-Gly-Arg-Gly-Lys-Gly-Gly-Lys-Gly-Leu-Gly-Lys-Gly-Gly-Ala-Lys-Arg-His-Arg-Lys-Val-Leu-Arg-Gly-Ser-Gly-Ser-Lys(Biotin)-OH

Molecular Weight: 3003.7

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C

Research Area: epigenetics

Source / Species: human

Conjugation: Conjugated

Conjugation Type: Biotins

Code Nacres: NA.26

Application: Histone H4 (1–23)-GSGSK(Biotin) corresponds to the N-terminal 23 amino acids of histone H4 and includes a C-terminal GSGS linker followed by a biotinylated lysine. The H4 N-terminal tail is a principal substrate for histone acetyltransferases and plays a central role in nucleosome stability and transcriptional regulation. Biotinylation enables efficient capture on streptavidin- or agarose-based matrices, supporting pull-down and enzymatic assays. This peptide is widely applied in histone acetyltransferase activity measurements, enzyme kinetics studies, and screening of chromatin-modifying enzymes. It serves as a versatile reagent for biochemical and epigenetic investigations of chromatin regulation.

Current Research: Chromatin structure and gene expression are tightly controlled by post-translational modifications of histone proteins. These chemical modifications regulate how DNA is packaged within nucleosomes and determine whether genomic regions are accessible to transcriptional machinery. Among the core histones, histone H4 plays a particularly important role in chromatin organization, largely due to its highly modifiable N-terminal tail. Synthetic peptides derived from histone tails have become indispensable reagents for studying the enzymes and regulatory proteins that control chromatin function. The Histone H4 (1–23)-GSGSK(Biotin) peptide provides a defined model substrate for investigating histone acetylation and chromatin-associated enzymatic activity. The Histone H4 N-Terminal Tail in Chromatin Regulation Histone H4 is one of the four core histone proteins that assemble into nucleosomes, the repeating structural units of chromatin. Each nucleosome contains approximately 147 base pairs of DNA wrapped around a histone octamer composed of two molecules each of H2A, H2B, H3, and H4. The N-terminal tails of these histones extend outward from the nucleosome core and serve as key regulatory regions. The N-terminal region of histone H4 is particularly rich in lysine residues, which are frequently modified by acetylation and other post-translational modifications. These chemical changes can alter chromatin structure by modifying interactions between histones and DNA, as well as by recruiting specialized chromatin-binding proteins. The first 23 amino acids of histone H4 represent one of the most important segments for regulatory modification. Multiple lysines within this region—including K5, K8, K12, and K16—are common targets of histone acetyltransferases (HATs), enzymes that transfer acetyl groups to histone tails and promote transcriptionally permissive chromatin states. Histone Acetylation and Gene Expression Histone acetylation is one of the most extensively studied epigenetic modifications. When histone acetyltransferases add acetyl groups to lysine residues, the positive charge of the lysine side chain is neutralized. This reduces electrostatic interactions between histones and the negatively charged DNA backbone, resulting in a more relaxed chromatin structure. The relaxed chromatin configuration facilitates access of transcription factors, RNA polymerase, and other regulatory proteins to DNA. In addition, acetylated lysines can be recognized by bromodomain-containing proteins, which function as reader modules that recruit transcriptional coactivators and chromatin remodeling complexes. Because histone H4 acetylation is closely linked to gene activation, understanding how HAT enzymes recognize and modify the H4 tail is a major focus of epigenetics research. Design and Features of the Synthetic Peptide The Histone H4 (1–23)-GSGSK(Biotin) peptide replicates the first 23 amino acids of the human histone H4 N-terminal tail, preserving the native sequence context that is recognized by chromatin-modifying enzymes. This design makes the peptide an ideal substrate for biochemical assays examining histone modification activity. At the C-terminus, the peptide contains a GSGS linker followed by a lysine residue modified with biotin. The glycine–serine linker introduces flexibility and spatial separation between the histone sequence and the biotin tag, helping ensure that the histone tail remains accessible for enzyme interactions and binding events. Biotin provides a highly efficient method for immobilizing the peptide through the strong interaction between biotin and streptavidin or avidin proteins. This interaction enables stable attachment of the peptide to streptavidin-coated surfaces, agarose beads, or affinity matrices used in biochemical experiments. Applications in Histone Acetyltransferase Assays One of the primary uses of the H4 (1–23) peptide is in histone acetyltransferase activity assays. In these experiments, purified HAT enzymes or cellular extracts are incubated with the peptide to measure enzymatic acetylation of lysine residues. Because the peptide contains multiple lysines within the native histone sequence, it provides a physiologically relevant substrate for evaluating enzyme activity. Researchers can use the peptide to measure reaction rates, determine substrate specificity, and compare the activity of different acetyltransferase enzymes. These assays contribute to understanding how enzymes such as p300/CBP, GCN5, and other chromatin-modifying proteins regulate histone acetylation patterns. Enzyme Kinetics and Screening Applications Beyond measuring basic enzyme activity, the peptide is also useful for enzyme kinetics studies. By varying substrate concentrations and reaction conditions, researchers can determine parameters such as catalytic efficiency and enzyme affinity for histone substrates. The peptide also supports screening experiments aimed at identifying modulators of chromatin-modifying enzymes. For example, biochemical assays using the H4 (1–23) peptide can be used to evaluate compounds that affect histone acetyltransferase activity or influence histone–protein interactions. These studies are particularly important for understanding how chromatin-modifying enzymes contribute to gene regulation and cellular signaling pathways. Applications in Chromatin Interaction Studies The biotin tag incorporated into the peptide enables a variety of affinity-based interaction assays. Immobilized peptides can be used in pull-down experiments to capture proteins that interact with the histone H4 tail. Such studies help identify histone-binding proteins, chromatin readers, and regulatory complexes that recognize specific histone sequences or modification patterns. The peptide therefore provides a simplified and controllable model system for investigating chromatin-associated interactions. Conclusion The Histone H4 (1–23)-GSGSK(Biotin) peptide is a versatile reagent designed to model the regulatory N-terminal region of histone H4 while enabling convenient experimental manipulation through biotin-based immobilization. By reproducing a key histone sequence targeted by acetyltransferases, the peptide serves as a valuable substrate for investigating histone modification activity, enzyme kinetics, and chromatin-associated protein interactions. Through applications in HAT activity assays, biochemical screening, and chromatin interaction studies, this peptide supports detailed exploration of epigenetic mechanisms that regulate chromatin structure and gene expression. Synthetic histone peptides such as this continue to provide essential tools for advancing research into the molecular basis of chromatin regulation.