Target type: molecularfunction
Catalysis of the reaction: H2O + histone H3 L-arginyl (position 8)= histone H3 L-citrullyl (position 8) + NH4+, resulting in histone H3 citrullination at position 8. [PMID:15339660]
Histone H3R8 arginine deiminase activity, also known as peptidylarginine deiminase 4 (PAD4) activity, is a post-translational modification that converts arginine residues to citrulline residues within histone H3. This modification is crucial for regulating chromatin structure and gene expression. PAD4 specifically targets the arginine residue at position 8 (R8) of histone H3.
The molecular function of PAD4 involves a complex enzymatic mechanism that utilizes calcium ions and a catalytic triad of amino acids. This activity is tightly regulated and is often associated with inflammatory responses, immune system activation, and cellular differentiation.
Upon binding to its substrate, histone H3, PAD4 undergoes a conformational change that exposes the catalytic site. This site contains the catalytic triad, which is composed of a cysteine, histidine, and aspartic acid residue. These residues facilitate the deimination reaction, where the guanidino group of arginine is converted to a urea group, resulting in the formation of citrulline.
The citrullination of histone H3R8 has a profound impact on chromatin structure and gene expression. Citrullination alters the charge distribution of the histone tail, leading to a weakened interaction between histone H3 and DNA. This weakened interaction results in a more open chromatin conformation, which allows for increased accessibility of transcription factors and other regulatory proteins to DNA.
The deimination of histone H3R8 has been implicated in various cellular processes, including:
- **Immune responses:** PAD4 activity is elevated in immune cells during inflammation, where it contributes to the production of pro-inflammatory cytokines and the activation of immune cells.
- **Cellular differentiation:** PAD4 is involved in the differentiation of various cell types, including immune cells and neuronal cells.
- **Cancer development:** Aberrant PAD4 activity has been linked to tumorigenesis and cancer progression in several types of cancer.
In summary, histone H3R8 arginine deiminase activity is a critical post-translational modification that regulates chromatin structure, gene expression, and cellular processes. The citrullination of histone H3R8 has a profound impact on these processes, making it a target of interest in the development of new therapeutic strategies for various diseases.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Protein-arginine deiminase type-4 | A protein-arginine deiminase type-4 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9UM07] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| azathioprine | azathioprine : A thiopurine that is 6-mercaptopurine in which the mercapto hydrogen is replaced by a 1-methyl-4-nitroimidazol-5-yl group. It is a prodrug for mercaptopurine and is used as an immunosuppressant, prescribed for the treatment of inflammatory conditions and after organ transplantation and also for treatment of Crohn's didease and MS. Azathioprine: An immunosuppressive agent used in combination with cyclophosphamide and hydroxychloroquine in the treatment of rheumatoid arthritis. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), this substance has been listed as a known carcinogen. (Merck Index, 11th ed) | aryl sulfide; C-nitro compound; imidazoles; thiopurine | antimetabolite; antineoplastic agent; carcinogenic agent; DNA synthesis inhibitor; hepatotoxic agent; immunosuppressive agent; prodrug |
| leflunomide | leflunomide : A monocarboxylic acid amide obtained by formal condensation of the carboxy group of 5-methyl-1,2-oxazole-4-carboxylic acid with the anilino group of 4-(trifluoromethyl)aniline. The prodrug of teriflunomide. Leflunomide: An isoxazole derivative that inhibits dihydroorotate dehydrogenase, the fourth enzyme in the pyrimidine biosynthetic pathway. It is used an immunosuppressive agent in the treatment of RHEUMATOID ARTHRITIS and PSORIATIC ARTHRITIS. | (trifluoromethyl)benzenes; isoxazoles; monocarboxylic acid amide | antineoplastic agent; antiparasitic agent; EC 1.3.98.1 [dihydroorotate oxidase (fumarate)] inhibitor; EC 3.1.3.16 (phosphoprotein phosphatase) inhibitor; hepatotoxic agent; immunosuppressive agent; non-steroidal anti-inflammatory drug; prodrug; pyrimidine synthesis inhibitor; tyrosine kinase inhibitor |
| mesalamine | mesalamine : A monohydroxybenzoic acid that is salicylic acid substituted by an amino group at the 5-position. Mesalamine: An anti-inflammatory agent, structurally related to the SALICYLATES, which is active in INFLAMMATORY BOWEL DISEASE. It is considered to be the active moiety of SULPHASALAZINE. (From Martindale, The Extra Pharmacopoeia, 30th ed) | amino acid; aromatic amine; monocarboxylic acid; monohydroxybenzoic acid; phenols | non-steroidal anti-inflammatory drug |
| streptonigrin | pyridines; quinolone | antimicrobial agent; antineoplastic agent | |
| sulfamethoxazole | sulfamethoxazole : An isoxazole (1,2-oxazole) compound having a methyl substituent at the 5-position and a 4-aminobenzenesulfonamido group at the 3-position. Sulfamethoxazole: A bacteriostatic antibacterial agent that interferes with folic acid synthesis in susceptible bacteria. Its broad spectrum of activity has been limited by the development of resistance. (From Martindale, The Extra Pharmacopoeia, 30th ed, p208) | isoxazoles; substituted aniline; sulfonamide; sulfonamide antibiotic | antibacterial agent; antiinfective agent; antimicrobial agent; drug allergen; EC 1.1.1.153 [sepiapterin reductase (L-erythro-7,8-dihydrobiopterin forming)] inhibitor; EC 2.5.1.15 (dihydropteroate synthase) inhibitor; environmental contaminant; epitope; P450 inhibitor; xenobiotic |
| sulfapyridine | sulfapyridine : A sulfonamide consisting of pyridine with a 4-aminobenzenesulfonamido group at the 2-position. Sulfapyridine: Antibacterial, potentially toxic, used to treat certain skin diseases. | pyridines; substituted aniline; sulfonamide; sulfonamide antibiotic | antiinfective agent; dermatologic drug; drug allergen; environmental contaminant; xenobiotic |
| trimethoprim | trimethoprim : An aminopyrimidine antibiotic whose structure consists of pyrimidine 2,4-diamine and 1,2,3-trimethoxybenzene moieties linked by a methylene bridge. Trimethoprim: A pyrimidine inhibitor of dihydrofolate reductase, it is an antibacterial related to PYRIMETHAMINE. It is potentiated by SULFONAMIDES and the TRIMETHOPRIM, SULFAMETHOXAZOLE DRUG COMBINATION is the form most often used. It is sometimes used alone as an antimalarial. TRIMETHOPRIM RESISTANCE has been reported. | aminopyrimidine; methoxybenzenes | antibacterial drug; diuretic; drug allergen; EC 1.5.1.3 (dihydrofolate reductase) inhibitor; environmental contaminant; xenobiotic |
| streptomycin | antibiotic antifungal drug; antibiotic fungicide; streptomycins | antibacterial drug; antifungal agrochemical; antimicrobial agent; antimicrobial drug; bacterial metabolite; protein synthesis inhibitor | |
| n-benzoyl-l-arginine | N-benzoyl-L-arginine : An N-acyl-L-arginine that is L-arginine in which one of the hydrogens attached to the alpha-amino group has been replaced by a benzoyl group. N-benzoyl-L-arginine: RM given refers to (l)-isomer; structure | benzamides; N-acyl-L-arginine | |
| benzoylarginine ethyl ester | benzoylarginine ethyl ester: used as substrate for trypsin; RN given refers to parent cpd | ||
| methotrexate | dicarboxylic acid; monocarboxylic acid amide; pteridines | abortifacient; antimetabolite; antineoplastic agent; antirheumatic drug; dermatologic drug; DNA synthesis inhibitor; EC 1.5.1.3 (dihydrofolate reductase) inhibitor; immunosuppressive agent | |
| benzoyl l-arginine methyl ester | benzoyl L-arginine methyl ester: RN given refers to (L-Arg)-isomer | ||
| n(alpha)-benzoylarginineamide | N(alpha)-benzoylarginineamide: RN given refers to parent cpd(S)-isomer | ||
| clindamycin | clindamycin : A carbohydrate-containing antibiotic that is the semisynthetic derivative of lincomycin, a natural antibiotic. Clindamycin: An antibacterial agent that is a semisynthetic analog of LINCOMYCIN. | ||
| zithromax | azithromycin : A macrolide antibiotic useful for the treatment of bacterial infections. Azithromycin: A semi-synthetic macrolide antibiotic structurally related to ERYTHROMYCIN. It has been used in the treatment of Mycobacterium avium intracellulare infections, toxoplasmosis, and cryptosporidiosis. | macrolide antibiotic | antibacterial drug; environmental contaminant; xenobiotic |
| n-alpha-benzoyl-n5-(2-chloro-1-iminoethyl)-l-ornithine amide | benzenes | ||
| tetracycline | tetracycline : A broad-spectrum polyketide antibiotic produced by the Streptomyces genus of actinobacteria. Tetracycline: A naphthacene antibiotic that inhibits AMINO ACYL TRNA binding during protein synthesis. | ||
| chlortetracycline | chlortetracycline : A member of the class of tetracyclines with formula C22H23ClN2O8 isolated from Streptomyces aureofaciens. Chlortetracycline: A TETRACYCLINE with a 7-chloro substitution. | ||
| minocycline | minocycline : A tetracycline analogue having a dimethylamino group at position 7 and lacking the methyl and hydroxy groups at position 5. Minocycline: A TETRACYCLINE analog, having a 7-dimethylamino and lacking the 5 methyl and hydroxyl groups, which is effective against tetracycline-resistant STAPHYLOCOCCUS infections. |