[Lys(Me3)4]-Histone H3 (1-25)-NH2

Product Name: [Lys(Me3)4]-Histone H3 (1-25)-NH2

Sequence One Letter Code: ART-K(Me3)-QTARKSTGGKAPRKQLATKAA-NH2

Sequence Three Letter Code: H-Ala-Arg-Thr-Lys(Me3)-Gln-Thr-Ala-Arg-Lys-Ser-Thr-Gly-Gly-Lys-Ala-Pro-Arg-Lys-Gln-Leu-Ala-Thr-Lys-Ala-Ala-NH2

Molecular Weight: 2668.3

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C

Research Area: epigenetics

Source / Species: human

Conjugation: Unconjugated

Code Nacres: NA.26

Application: This synthetic peptide corresponds to residues 1–25 of human histone H3 and contains trimethylation at lysine 4 (H3K4me3), a signature mark of transcriptionally active and poised promoters. H3K4me3 plays a critical role in defining gene expression states, lineage specification, and imprinting control regions. The peptide is widely used to study chromatin signaling pathways, recruitment of H3K4me3-specific reader proteins, and epigenetic memory mechanisms. It is suitable for binding assays, structural characterization, and validation of methylation-specific antibodies. This reagent supports mechanistic studies of transcriptional regulation and developmental epigenetics.

Current Research: Epigenetic modifications of histone proteins play a central role in regulating gene expression and chromatin organization. Among the numerous histone marks identified across eukaryotic genomes, trimethylation of lysine 4 on histone H3 (H3K4me3) is one of the most extensively studied. This modification is strongly associated with transcriptionally active and poised promoters, marking genomic regions that are accessible for transcription initiation. Synthetic peptides containing defined histone modifications have become indispensable reagents for investigating the molecular mechanisms that interpret these epigenetic signals. The H3K4me3 peptide corresponding to residues 1–25 of human histone H3 provides a well-defined substrate for studying transcriptional regulation and chromatin signaling pathways. Histone H3 and the Epigenetic Landscape Histone H3 is a core component of nucleosomes, the repeating structural units that package DNA into chromatin. Each nucleosome consists of approximately 147 base pairs of DNA wrapped around an octamer composed of two molecules each of histones H2A, H2B, H3, and H4. The N-terminal tail of histone H3 extends outward from the nucleosome surface and is accessible to numerous enzymes that install or remove regulatory modifications. This histone tail contains several lysine residues that are targets for methylation and acetylation. These modifications influence chromatin structure and recruit proteins that regulate transcription, DNA repair, and genome organization. Because histone modifications can act as molecular signals for downstream regulatory events, they are often described as part of the “histone code,” a combinatorial system that governs chromatin function. The region spanning residues 1–25 of histone H3 contains lysine 4, one of the most important methylation sites associated with gene activation. Biological Significance of H3K4 Trimethylation H3K4 trimethylation (H3K4me3) is a hallmark epigenetic modification found near the promoters of actively transcribed genes. Genome-wide mapping studies have consistently shown that H3K4me3 is enriched at transcription start sites, where it helps define regions that are accessible to transcription factors and RNA polymerase complexes. Unlike acetylation, methylation does not change the charge of lysine residues. Instead, the addition of methyl groups alters the chemical surface of the histone tail, creating specific recognition sites for chromatin-associated proteins. Many of these proteins contain specialized domains—such as plant homeodomain (PHD) fingers, chromodomains, and Tudor domains—that selectively bind methylated lysine residues. Through these interactions, H3K4me3 functions as a recruitment platform for transcriptional regulatory complexes, linking histone modification patterns to gene activation pathways. Role in Gene Expression and Development The presence of H3K4me3 at promoter regions reflects the transcriptional state of genes. Active genes typically display strong enrichment of this mark, while genes that are poised for activation may retain moderate levels of H3K4me3 in combination with other histone modifications. This modification is particularly important in developmental gene regulation, where dynamic changes in histone methylation patterns help control lineage specification and cellular differentiation. For example, embryonic stem cells often exhibit unique chromatin states in which activating marks like H3K4me3 coexist with repressive modifications at developmental gene promoters. H3K4me3 also plays a role in genomic imprinting, where epigenetic marks regulate parent-of-origin–specific gene expression. By influencing chromatin accessibility and transcriptional competence, the modification contributes to the maintenance of epigenetic memory across cell divisions. Design of the Synthetic H3K4me3 Peptide The H3 (1–25) K4me3 peptide reproduces the N-terminal region of human histone H3 while incorporating a precisely defined trimethyl modification at lysine 4. This design allows researchers to study the biochemical consequences of this epigenetic mark in a controlled experimental setting. Because the peptide contains the native sequence context surrounding lysine 4, it faithfully represents the region recognized by methylation-specific reader proteins and regulatory complexes. The defined structure ensures reproducibility in assays aimed at examining histone–protein interactions and epigenetic signaling mechanisms. Synthetic peptides also allow researchers to isolate the effect of a single histone modification without interference from other chromatin components. Applications in Chromatin Interaction Studies One of the primary uses of the H3K4me3 peptide is in binding assays that investigate interactions between histone modifications and chromatin reader proteins. By incubating the peptide with purified proteins or cellular extracts, researchers can identify factors that specifically recognize the H3K4me3 modification. These studies help elucidate how transcriptional regulators and chromatin remodeling complexes are recruited to active promoters. Understanding these interactions is essential for deciphering the molecular mechanisms that control gene activation. Structural and Biophysical Characterization The peptide is also useful in structural biology studies, where researchers examine how reader domains interact with methylated histone residues at the atomic level. Techniques such as nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography often use synthetic peptides as model substrates. These structural studies provide detailed insights into how methylation-specific recognition occurs and how subtle differences in histone modification patterns influence protein binding. Validation of Methylation-Specific Antibodies Another important application of the H3K4me3 peptide is validation of modification-specific antibodies. Antibodies used in chromatin research must accurately distinguish between different methylation states of lysine residues, such as mono-, di-, and trimethylation. Synthetic peptides containing defined modifications serve as reliable reference standards for evaluating antibody specificity in assays such as western blotting, ELISA, and chromatin immunoprecipitation (ChIP). Ensuring antibody accuracy is critical for interpreting experimental results in epigenetic research. Supporting Studies of Epigenetic Memory Because H3K4me3 is associated with stable transcriptional states, it is often studied in the context of epigenetic memory—the ability of cells to maintain gene expression patterns through successive cell divisions. Synthetic peptides provide a simplified system for exploring how histone modifications contribute to the maintenance and inheritance of chromatin states. Conclusion The H3K4me3 peptide corresponding to histone H3 residues 1–25 represents a powerful experimental tool for investigating epigenetic regulation and transcriptional activation. By incorporating trimethylation at lysine 4, the peptide models a key histone modification associated with active promoter regions and gene expression control. Its applications span protein–histone interaction studies, structural characterization of methyl-lysine recognition, antibody validation, and mechanistic analyses of chromatin signaling pathways. As research continues to uncover the complex networks governing gene regulation and development, defined histone peptides like H3K4me3 remain essential for understanding the biochemical foundations of epigenetic control.