[Cit 2/8/17]-Histone H3 (1-21)-GGK(Biotin)-NH2

Product Name: [Cit 2/8/17]-Histone H3 (1-21)-GGK(Biotin)-NH2 - 0.25 mg

Sequence One Letter Code: A-Cit-TKQTA-Cit-KSTGGKAP-Cit-KQLA-GGK(Biotin)-NH2

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

Molecular Weight: 2725.3

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 H3 (1–21) R2/8/17Cit-GGK(Biotin)-NH₂ is a synthetic peptide derived from the N-terminal tail of histone H3 containing citrullination at arginine residues 2, 8, and 17. These modifications are introduced by the enzyme PADI4 and result in the conversion of arginine to citrulline, preventing arginine methylation at these positions. Multi-site citrullination of histone H3 has been linked to transcriptional repression and regulation of chromatin accessibility. The peptide includes a C-terminal GGK linker with biotinylation and an amide cap, enabling efficient immobilization and detection in streptavidin-based assays. It is widely used to study the biological consequences of histone citrullination, epigenetic modification cross-talk, and the mechanisms by which arginine-modifying enzymes regulate chromatin structure and gene expression.

Current Research: Histone post-translational modifications (PTMs) are fundamental regulators of chromatin structure and gene expression. These chemical marks alter histone–DNA interactions and recruit regulatory proteins that control transcription, DNA repair, and genome organization. Among these modifications, histone citrullination has emerged as an important mechanism influencing chromatin accessibility and transcriptional regulation. Synthetic peptides that replicate specific histone modification patterns allow researchers to analyze these mechanisms in controlled experimental systems. Histone H3 (1–21) R2/8/17Cit-GGK(Biotin)-NH₂ is a synthetic peptide corresponding to the N-terminal tail of histone H3 with citrullination at arginine residues 2, 8, and 17, combined with a C-terminal GGK-biotin linker and amide cap. This design provides a useful model substrate for investigating how multi-site citrullination influences chromatin signaling and histone recognition. The Regulatory Role of the Histone H3 N-Terminal Tail Histone H3 is a key component of the nucleosome, the structural unit of chromatin in which DNA is wrapped around histone proteins. The N-terminal tail of histone H3 extends from the nucleosome surface and contains numerous residues that undergo post-translational modification. These modifications contribute to the histone code, a regulatory framework in which combinations of chemical marks determine how chromatin-associated proteins interact with histones. Within the first 20 amino acids of histone H3, several arginine and lysine residues act as modification sites that influence transcriptional activity and chromatin structure. Modifications in this region can regulate gene expression by altering chromatin compaction or by recruiting regulatory complexes involved in transcriptional activation or repression. Synthetic peptides representing this region are widely used to study how specific modifications affect histone recognition and epigenetic signaling. Citrullination and the Role of PADI4 Citrullination, also referred to as arginine deimination, is a biochemical process in which arginine residues are converted into citrulline. This reaction is catalyzed by a family of enzymes known as peptidylarginine deiminases (PADIs), with PADI4 functioning as a major nuclear enzyme responsible for modifying histones. During citrullination, the positively charged guanidinium group of arginine is converted into a neutral ureido group. This conversion significantly alters the electrostatic properties and hydrogen bonding capacity of the residue. Because histone–DNA interactions rely heavily on electrostatic forces, this modification can influence chromatin structure and protein binding. Citrullination of histone H3 at R2, R8, and R17 has been observed in chromatin and is associated with regulatory changes in gene expression. Importantly, this modification prevents arginine methylation, since citrulline cannot serve as a substrate for arginine methyltransferases. As a result, citrullination acts as a competitive modification that alters the epigenetic landscape. Multi-Site Citrullination and Epigenetic Cross-Talk The simultaneous citrullination of multiple arginine residues within the histone H3 tail can have significant effects on chromatin behavior. Multi-site citrullination at R2, R8, and R17 is thought to influence transcriptional regulation by modifying histone–protein interactions and reducing the availability of methylation sites. Because arginine methylation at these positions is often associated with transcriptional activation, their conversion to citrulline can contribute to transcriptional repression or chromatin remodeling. This interplay between modifications represents an example of epigenetic cross-talk, where one modification influences the occurrence or recognition of another. Studying these interactions is essential for understanding how chromatin regulatory systems integrate multiple signals to control gene expression. Structural Design of the Peptide The Histone H3 (1–21) R2/8/17Cit-GGK(Biotin)-NH₂ peptide is designed to replicate the biologically relevant histone sequence while incorporating features that facilitate experimental analysis. Key components include: Residues 1–21 of histone H3, representing the regulatory N-terminal region Citrullination at arginine residues 2, 8, and 17, mimicking the modified histone state A C-terminal GGK linker, providing spatial separation from the affinity tag Biotin attached to the lysine residue, enabling affinity capture An amide cap (-NH₂) at the C-terminus to stabilize the peptide structure The linker helps maintain the native interaction surface of the histone sequence while allowing the peptide to be easily immobilized in experimental systems. Advantages of Biotinylated Histone Peptides Biotinylation provides a powerful strategy for studying histone interactions. Biotin binds with extremely high affinity to streptavidin or avidin, enabling efficient capture and immobilization in biochemical assays. This feature supports a wide range of experimental approaches, including: Pull-down assays to isolate histone-binding proteins Affinity purification of chromatin-associated complexes Protein interaction mapping Proteomics workflows, including mass spectrometry analysis Surface immobilization for biophysical studies These capabilities make biotinylated peptides valuable tools for identifying proteins that recognize specific histone modification states. Applications in Chromatin and Epigenetics Research The Histone H3 (1–21) R2/8/17Cit-GGK(Biotin)-NH₂ peptide is commonly used in studies investigating the biological roles of histone citrullination and arginine modification pathways. Typical applications include: Histone modification cross-talk studies Researchers use the peptide to examine how citrullination influences or blocks arginine methylation and other histone modifications. Protein interaction analysis The peptide enables identification of proteins that recognize citrullinated histone tails or respond to changes in arginine modification states. PADI enzyme research The peptide serves as a model substrate for studying the activity and specificity of PADI4 and related enzymes. Chromatin remodeling investigations Understanding how citrullinated histone tails interact with chromatin regulators helps clarify mechanisms controlling nucleosome dynamics and chromatin accessibility. Enabling Deeper Insights into Epigenetic Regulation Epigenetic regulation involves complex interactions between multiple histone modifications and chromatin-associated proteins. Synthetic histone peptides that replicate specific modification patterns provide a controlled platform for investigating these mechanisms. By incorporating triple citrullination within the histone H3 N-terminal tail along with a biotin affinity tag, the Histone H3 (1–21) R2/8/17Cit-GGK(Biotin)-NH₂ peptide offers a versatile tool for exploring how arginine-modifying enzymes influence chromatin organization and gene regulation. Through applications in interaction studies, enzyme assays, and chromatin signaling research, this peptide supports ongoing efforts to understand the epigenetic processes that govern genome function.