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Recombinant Proteins & Enzymes

Histones and Modified Histones

recombinant histone proteins for chromatin assays

Active Motif offers a wide variety of recombinant histones that include site- and degree-specific modifications such as methylation, acetylation and phosphorylation. The combination of histone post-translational modifications form the basis of the “histone code” that serves to regulate a variety of nuclear functions, including interactions with chromatin-associated proteins, nucleosome remodeling, transcriptional regulation, replication and DNA repair. Each recombinant histone is prepared using one of two patented technologies:  Expressed Protein Ligation (EPL) or Methylated Lysine Analog (MLA). We also offer a subset of our histone H3 proteins that have been biotinylated for use in FRET assays and other capture techniques.

With our MLA technology, methylated histones are generated via a chemical alkylation reaction that introduces a methyl-lysine analog at the desired lysine location, giving us precise control over the site and degree of methylation. Alternatively, the EPL technology can be used to generate methylated, acetylated and phosphorylated histones. Using EPL, the histone globular domain is ligated to a peptide that contains the N-terminal histone tail with the desired modifications. This ligation reaction maintains the native histone bonds. Both methods produce proteins that are validated to be over 98% pure. For more information on the EPL and MLA technologies, click on the EPL and MLA Technologies tab below.

Active Motif also offers a number of biotinylated recombinant histone H3 proteins. Biotin is linked either to unmodified or modified recombinant H3 protein at its N-terminus via a carbon linker. The addition of biotin enables the recombinant histones to be used as a substrate for capture of protein binding interactions. Biotinylated histone H3 proteins are also ideal substrates for homogenous FRET assays. Simply incubate the recombinant histone with the enzyme of interest and detect using streptavidin-coated donor beads and antibody-conjugated acceptor beads.

A complete list of recombinant histones is shown below. Click on the protein name to see complete information.

 
Name Expressed In Format Cat No. Price  
Recombinant Histone H2A (Human) E. coli 100 µg 31490 $90 Buy Now
Recombinant Histone H2A (Xenopus) E. coli 50 µg 31251 $385 Buy Now
Recombinant Histone H2A.Z Synthetic 25 µg 31293 $385 Buy Now
Recombinant Histone H2B (Human) E. coli 100 µg 31492 $90 Buy Now
Recombinant Histone H2B (Xenopus) E. coli 50 µg 31252 $385 Buy Now
Recombinant Histone H3 (C110A) E. coli 100 µg 31207 $385 Buy Now
Recombinant Histone H3 pan-acetyl Synthetic 25 µg 31289 $385 Buy Now
Recombinant Histone H3.1 (Human) E. coli 100 µg 31294 $90 Buy Now
Recombinant Histone H3.1 biotinylated (Human) E. coli 100 µg 31296 $95 Buy Now
Recombinant Histone H3.2 biotinylated (Human) E. coli 25 µg 31271 $385 Buy Now
Recombinant Histone H3.3 (Human) E. coli 100 µg 31295 $90 Buy Now
Recombinant Histone H3.3 biotinylated (Human) E. coli 100 µg 31297 $95 Buy Now
Recombinant Histone H3T3ph (EPL) E. coli 25 µg 31274 $385 Buy Now
Recombinant Histone H3K4ac (EPL) E. coli 25 µg 31275 $385 Buy Now
Recombinant Histone H3K4me1 (MLA) E. coli 50 µg 31208 $385 Buy Now
Recombinant Histone H3K4me1 biotinylated (EPL) E. coli 25 µg 31284 $385 Buy Now
Recombinant Histone H3K4me2 (EPL) E. coli 25 µg 31277 $385 Buy Now
Recombinant Histone H3K4me2 (MLA) E. coli 50 µg 31209 $385 Buy Now
Recombinant Histone H3K4me2 biotinylated (EPL) E. coli 25 µg 31283 $385 Buy Now
Recombinant Histone H3K4me3 (EPL) E. coli 25 µg 31278 $385 Buy Now
Recombinant Histone H3K4me3 (MLA) E. coli 50 µg 31210 $385 Buy Now
Recombinant Histone H3K4me3 biotinylated (EPL) E. coli 25 µg 31282 $385 Buy Now
Recombinant Histone H3R8me2a (asymmetric) (EPL) E. coli 25 µg 31276 $385 Buy Now
Recombinant Histone H3K9ac (EPL) E. coli 25 µg 31253 $385 Buy Now
Recombinant Histone H3K9me1 (EPL) E. coli 25 µg 31281 $385 Buy Now
Recombinant Histone H3K9me1 (MLA) E. coli 50 µg 31211 $385 Buy Now
Recombinant Histone H3K9me1 biotinylated (EPL) E. coli 25 µg 31286 $385 Buy Now
Recombinant Histone H3K9me2 (EPL) E. coli 25 µg 31280 $385 Buy Now
Recombinant Histone H3K9me2 (MLA) E. coli 50 µg 31212 $385 Buy Now
Recombinant Histone H3K9me3 (EPL) E. coli 25 µg 31279 $385 Buy Now
Recombinant Histone H3K9me3 (MLA) E. coli 50 µg 31213 $385 Buy Now
Recombinant Histone H3K9me3 biotinylated (EPL) E. coli 25 µg 31285 $385 Buy Now
Recombinant Histone H3S10ph (EPL) E. coli 25 µg 31272 $385 Buy Now
Recombinant Histone H3K14ac (EPL) E. coli 25 µg 31254 $385 Buy Now
Recombinant Histone H3K14me1 (MLA) E. coli 50 µg 31256 $385 Buy Now
Recombinant Histone H3K14me2 (MLA) E. coli 50 µg 31257 $385 Buy Now
Recombinant Histone H3K14me3 (MLA) E. coli 50 µg 31258 $385 Buy Now
Recombinant Histone H3K18ac (EPL) E. coli 25 µg 31273 $385 Buy Now
Recombinant Histone H3K18me1 (MLA) E. coli 50 µg 31259 $385 Buy Now
Recombinant Histone H3K18me2 (MLA) E. coli 50 µg 31260 $385 Buy Now
Recombinant Histone H3K18me3 (MLA) E. coli 50 µg 31261 $385 Buy Now
Recombinant Histone H3K23ac (EPL) E. coli 25 µg 31255 $385 Buy Now
Recombinant Histone H3K23me1 (MLA) E. coli 50 µg 31262 $385 Buy Now
Recombinant Histone H3K23me2 (MLA) E. coli 50 µg 31263 $385 Buy Now
Recombinant Histone H3K23me3 (MLA) E. coli 50 µg 31264 $385 Buy Now
Recombinant Histone H3K27ac Synthetic 25 µg 31290 $385 Buy Now
Recombinant Histone H3K27me1 (MLA) E. coli 50 µg 31214 $385 Buy Now
Recombinant Histone H3K27me2 (MLA) E. coli 50 µg 31215 $385 Buy Now
Recombinant Histone H3K27me3 (MLA) E. coli 50 µg 31216 $385 Buy Now
Recombinant Histone H3K36me2 (MLA) E. coli 50 µg 31218 $385 Buy Now
Recombinant Histone H3K36me3 (MLA) E. coli 50 µg 31219 $385 Buy Now
Recombinant Histone H3K79me1 (MLA) E. coli 50 µg 31220 $385 Buy Now
Recombinant Histone H3K79me2 (MLA) E. coli 50 µg 31221 $385 Buy Now
Recombinant Histone H3K79me3 (MLA) E. coli 50 µg 31222 $385 Buy Now
Recombinant Histone H4 (Xenopus) E. coli 50 µg 31223 $385 Buy Now
Recombinant Histone H4, His-tag (Human) E. coli 100 µg 31493 $90 Buy Now
Recombinant Histone H4R3me2a Synthetic 25 µg 31291 $385 Buy Now
Recombinant Histone H4K5me1 (MLA) E. coli 50 µg 31265 $385 Buy Now
Recombinant Histone H4K5me2 (MLA) E. coli 50 µg 31266 $385 Buy Now
Recombinant Histone H4K5me3 (MLA) E. coli 50 µg 31267 $385 Buy Now
Recombinant Histone H4K16ac Synthetic 25 µg 31292 $385 Buy Now
Recombinant Histone H4K16me1 (MLA) E. coli 50 µg 31268 $385 Buy Now
Recombinant Histone H4K16me2 (MLA) E. coli 50 µg 31269 $385 Buy Now
Recombinant Histone H4K16me3 (MLA) E. coli 50 µg 31270 $385 Buy Now
Recombinant Histone H4K20me1 (MLA) E. coli 50 µg 31224 $385 Buy Now
Recombinant Histone H4K20me2 (MLA) E. coli 50 µg 31225 $385 Buy Now
Recombinant Histone H4K20me3 (MLA) E. coli 50 µg 31226 $385 Buy Now
Recombinant Histone Octamer (H3.1) E. coli 100 µg 31470 $395 Buy Now
Recombinant Histone Octamer (H3.1) - biotinylated E. coli 50 µg 31471 $470 Buy Now
Recombinant Histone Octamer (H3.3) E. coli 100 µg 31472 $395 Buy Now
Recombinant Histone Octamer (H3.3) - biotinylated E. coli 50 µg 31473 $470 Buy Now

The ability to alter protein structure through the introduction of synthetic modifications is a powerful technique that can be utilized to dissect protein function and to facilitate the generation of research tools or therapeutic reagents. Chemical synthesis of peptides is a technically demanding process and also restricts the size of the generated protein. Therefore, a more robust technique is required to generate large modified proteins, such as histones.

Current methods used for constructing modified recombinant histones include solid phase peptide synthesis (SPPS), reductive alkylation and semisynthetic methods that utilize transferases to catalyze the transfer of modified groups to specified residues. However these methods have their disadvantages, including:

  • Size limitation of the synthesized protein
  • The availability of the transferase enzyme
  • Variability in the degree of modifications catalyzed by the reaction
  • Heterogeneity in the specificity of the enzyme

EPL and MLA Technologies

To overcome these limitations, Active Motif’s recombinant histones are engineered using one of two patented technologies: Expressed Protein Ligation (EPL) or Methylated Lysine Analog (MLA).

EPL is a semisynthetic method in which an expressed protein (rather than a synthesized peptide with limited fragment size) containing an unprotected C-terminal thioester is ligated to a peptide containing an N-terminal cysteine via a chemoselective reaction. The reaction, known as ‘native chemical ligation,’ preserves the native amine bond. In the case of recombinant histones, this involves the ligation of a histone tail containing the site-specific modification to the globular histone globular domain. Along with preserving the natural protein structure, this method allows for the engineering of large synthetic proteins and permits incorporation of a broad range of histone modifications found in nature.

Generation of modified recombinant histones using the EPL Method

Click on image to enlarge size.

Figure 1: Generation of modified recombinant histones using the EPL method.

Expressed protein ligation (EPL) is used to synthesize full-length modified recombinant H3 histone proteins. A synthetic N-terminal peptide containing the post-translational modification (PTM) and an alanine (Ala)-conjugated thioester (activated) is ligated to a cysteine (Cys)-containing expressed C-terminal histone H3 globular domain through a series of reactions that preserve the native peptide bonds.

Using the alternative MLA technology, methylated histones are generated via a chemical alkylation reaction that substitutes a methylated analog of lysine, aminoethylcysteine, for the existing lysine at the desired residue. Aminoethylcysteine is structurally and chemically similar to lysine, though it contains an ethylamine substitution in place of the lysine ϒ-methylene. The lysine analogs can be chemically treated for engineering of modified histones to provide precise control over the site and degree of methylation. Studies demonstrate that modified histones engineered using the MLA technique show functional similarity to their natural counterparts.

Comparison of the chemical structures of Lysine and  Methyl-Lysine Analogs

Click on image to enlarge size.

Figure 2: Comparison of the chemical structures of lysine and methyl-lysine analogs.

The image depicts the similarities in the chemical structure of lysine and and the lysine analog, aminoethylcysteine. Aminoethylcysteine contains and ethylamine substitution (highlighted in gray) in place of the lysine ϒ-methylene (highlighted in gray). Alkylation of the ethylamine residue converts aminoethylcysteine into mono-, di- and tri-methyl lysine analogs (Me=methyl, in red).

Comparison of histone H3K4me2 peptide versus recombinant H3K4me2 protein as LSD1 susbstrate.
 
Figure 3: Comparison of the performance of histone substrates in a histone demethylase assay reveal recombinant histone H3K4me2 protein (MLA) more closely mimics native histone substrates.

The positive control LSD1 enzyme from the Histone Demethylase Assay (Cat No. 53200) was used to assay for demethylase activity using either a histone H3K4me2 peptide or the included recombinant histone H3K4me2 (MLA) protein (Cat No. 31209). One µg of LSD1 was tested with either 70 µM H3K4me2 peptide or with 13 µM recombinant histone H3K4me2 protein generated using MLA technology. LSD1 was able to convert 73% of the recombinant histone H3K4me2 protein substrate into formaldehyde, yet it was only able to convert 14% of the H3K4me2 peptide into formaldehdye, even though there was 5-fold more peptide available than recombinant protein for the same amount of LSD1 enzyme. The higher rates of conversion achieved from the use of the recombinant histone H3K4me2 (MLA) protein more closely resemble in vivo conditions and demonstrate the high level of functional similarity between modified histones generated using MLA techniques and native histones.

 

References

  1. Lin, J.C. et al. (2007) Cancer Cell, 12: 432-444.
  2. Muir, T.W. (2003) Annu Rev Biochem, 72: 249-289

* The MLA technology is covered under U.S. Patent No. 8,278,112. EPL patent is pending.