[Lys(Ac)16]-Histone H4 (1-20)

Product Name: [Lys(Ac)16]-Histone H4 (1-20)

Sequence One Letter Code: SGRGKGGKGLGKGGA-K(Ac)-RHRK

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

Molecular Weight: 2034.5

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 1–20 of histone H4 and contains site-specific acetylation at lysine 16 (H4K16ac), a uniquely influential chromatin modification. Unlike many other acetylation marks, H4K16 acetylation directly modulates higher-order chromatin folding and nucleosome compaction. It plays a central role in regulating gene transcription, chromatin accessibility, and genome stability. Certain histone acetyltransferase complexes display strong substrate preference for this residue, underscoring its biological specificity. This peptide is well suited for histone acetyltransferase assays, chromatin structure studies, and investigations of acetyl-lysine reader protein interactions involved in epigenetic regulation.

Current Research: Post-translational modifications of histones play a critical role in controlling chromatin structure and gene expression. Among these modifications, acetylation of lysine 16 on histone H4 (H4K16ac) stands out as one of the most influential marks in chromatin biology. Unlike many histone acetylation sites that primarily affect protein recruitment, H4K16 acetylation directly alters higher-order chromatin folding and nucleosome interactions. Synthetic peptides containing defined histone modifications provide powerful tools for studying these mechanisms. The Histone H4 (1–20) peptide with site-specific acetylation at lysine 16 reproduces a key regulatory region of the H4 tail and is widely used in biochemical assays examining chromatin signaling and epigenetic regulation. Histone H4 and the Regulatory N-Terminal Tail Histone H4 is one of the four core histone proteins that assemble into nucleosomes, the repeating units of chromatin. Each nucleosome contains approximately 147 base pairs of DNA wrapped around a histone octamer composed of two copies each of histones H2A, H2B, H3, and H4. The N-terminal tail of histone H4 extends from the nucleosome surface and serves as a critical platform for regulatory post-translational modifications. This tail contains several lysine residues—such as K5, K8, K12, and K16—that can undergo acetylation by histone acetyltransferases (HATs). These modifications influence chromatin organization by altering histone–DNA interactions and recruiting regulatory proteins involved in transcription and chromatin remodeling. The peptide spanning residues 1–20 of histone H4 captures a major portion of this regulatory tail, including lysine 16, one of the most functionally significant histone modification sites. Unique Biological Significance of H4K16 Acetylation While many histone acetylation marks primarily influence gene expression through recruitment of acetyl-lysine–binding proteins, H4K16 acetylation has a direct structural effect on chromatin architecture. In unmodified chromatin, the positively charged lysine 16 side chain participates in interactions that promote tight packing of nucleosomes. Acetylation neutralizes this charge, disrupting interactions between the H4 tail and neighboring nucleosomes. As a result, chromatin fibers adopt a more open configuration. This structural change affects higher-order chromatin folding, reducing nucleosome compaction and increasing accessibility of DNA to transcription factors and regulatory complexes. Because of this property, H4K16ac is widely associated with active chromatin regions and transcriptional activation. Role in Gene Expression and Genome Stability Beyond its structural effects, H4K16 acetylation participates in multiple cellular processes related to chromatin regulation. The modification is enriched at actively transcribed genes and regulatory regions where chromatin accessibility is required. H4K16ac also contributes to genome stability and DNA repair pathways. During cellular stress or DNA damage, changes in histone acetylation patterns can facilitate chromatin remodeling that allows repair proteins to access damaged DNA sites. In addition, alterations in H4K16 acetylation have been linked to aging and disease states, highlighting the importance of this modification in maintaining proper epigenetic regulation. Substrate Recognition by Histone Acetyltransferases Several histone acetyltransferase complexes display strong substrate specificity for lysine 16 of histone H4. These enzymes catalyze the transfer of acetyl groups from acetyl-CoA to lysine residues within histone tails. Because H4K16 represents a particularly important regulatory site, studying how acetyltransferases recognize and modify this residue provides valuable insight into enzyme specificity and chromatin regulation. Synthetic peptides containing the H4 (1–20) sequence with defined modifications allow researchers to examine these interactions in controlled experimental systems. Applications in Histone Acetyltransferase Assays One major application of the H4 (1–20) K16ac peptide is in histone acetyltransferase assays. In these experiments, researchers evaluate how enzymes interact with histone substrates and measure catalytic activity under defined conditions. The peptide can be used to study enzyme binding, substrate recognition, and modification kinetics. By comparing acetylated and unmodified peptides, investigators can determine how specific residues influence enzyme interactions and catalytic efficiency. These assays contribute to understanding the mechanisms governing histone modification patterns in chromatin. Investigating Acetyl-Lysine Reader Proteins Acetylated lysine residues are recognized by bromodomain-containing proteins, which function as reader modules in epigenetic signaling pathways. These proteins bind acetylated histones and recruit transcriptional regulators, chromatin remodeling complexes, or other regulatory factors. The H4K16ac peptide provides a defined ligand for examining interactions between acetylated histone tails and bromodomains or other acetyl-lysine–binding domains. Such studies help clarify how histone modifications are interpreted by cellular machinery to regulate transcription. Chromatin Structure and Biophysical Studies Because H4K16 acetylation directly influences chromatin folding, peptides representing this modification are frequently used in biophysical and structural studies of chromatin architecture. Researchers use these peptides to examine how histone modifications affect nucleosome interactions and chromatin compaction. Experimental approaches such as fluorescence assays, structural modeling, and interaction studies often rely on synthetic peptides to isolate the effect of individual modifications. Conclusion The Histone H4 (1–20) peptide containing acetylation at lysine 16 (H4K16ac) represents a valuable tool for exploring one of the most influential modifications in chromatin biology. By modeling a key region of the histone H4 N-terminal tail, the peptide allows researchers to examine how acetylation at lysine 16 influences chromatin structure, transcriptional regulation, and genome stability. Its applications include histone acetyltransferase assays, studies of acetyl-lysine reader protein interactions, and investigations into chromatin compaction and epigenetic signaling pathways. Through these studies, H4K16ac peptides continue to support research aimed at understanding the molecular mechanisms that regulate chromatin organization and gene expression.