Biomaterial Database

Location of the S-adenosyl-L-methionine binding region of the vaccinia virus mRNA (guanine-7-)methyltransferase. 1994

M A Higman, and E G Niles

Department of Biochemistry, State University of New York, School of Medicine and Biomedical Sciences, Buffalo 14214.

The mRNA (guanine-7-)methyltransferase activity of the heterodimeric vaccinia virus mRNA capping enzyme was previously mapped to the carboxyl-terminal 396 amino acids of the large subunit, D1R. This activity is enhanced 30- to 50-fold by the association of the the small subunit, D12L (Higman, M. A., Christen, L. A., and Niles, E. G. (1994) J. Biol. Chem. 269, 14974-14981). Irradiation with ultraviolet light specifically photolinks S-[methyl-3H]S-adenosyl-L-methionine to the large subunit of both the intact capping enzyme and a methyltransferase subdomain, which consists of the D12L subunit associated with the carboxyl-terminal 346 amino acids of the D1R subunit. The extent of linkage was shown to be dependent on the length of incubation, intensity of ultraviolet light, and the concentration of both active enzyme and substrate. The covalent modification was inhibited by S-adenosyl-L-homocysteine, a known competitive inhibitor of the mRNA (guanine-7-)methyltransferase activity, demonstrating specific photolabeling of the active site. Sequence-specific chemical cleavage of the photolinked methyltransferase domain with mild acid or cyanogen bromide revealed linkage of S-adenosyl-L-methionine to two regions of the large subunit. Analysis of the products of cyanogen bromide and hydroxylamine cleavage mapped the photolinked fragments to amino acids 499 to 579 and 806 to 844 of the D1R subunit. Photolinkage of AdoMet to D1R498-844 was shown to be unaffected by the association of the small subunit.

UI	MeSH Term	Description	Entries
D008780	Methyltransferases	A subclass of enzymes of the transferase class that catalyze the transfer of a methyl group from one compound to another. (Dorland, 28th ed) EC 2.1.1.	Methyltransferase
D009097	Multienzyme Complexes	Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.	Complexes, Multienzyme
D009713	Nucleotidyltransferases	A class of enzymes that transfers nucleotidyl residues. EC 2.7.7.	Nucleotidyltransferase
D010744	Phosphoric Monoester Hydrolases	A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate.	Phosphatase,Phosphatases,Phosphohydrolase,Phosphohydrolases,Phosphomonoesterase,Phosphomonoesterases,Phosphoric Monoester Hydrolase,Hydrolase, Phosphoric Monoester,Hydrolases, Phosphoric Monoester,Monoester Hydrolase, Phosphoric
D010777	Photochemistry	A branch of physical chemistry which studies chemical reactions, isomerization and physical behavior that may occur under the influence of visible and/or ultraviolet light.	Photochemistries
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D012436	S-Adenosylmethionine	Physiologic methyl radical donor involved in enzymatic transmethylation reactions and present in all living organisms. It possesses anti-inflammatory activity and has been used in treatment of chronic liver disease. (From Merck, 11th ed)	AdoMet,Ademetionine,FO-1561,Gumbaral,S Amet,S-Adenosyl-L-Methionine,S-Adenosylmethionine Sulfate Tosylate,SAM-e,Samyr,FO 1561,FO1561,S Adenosyl L Methionine,S Adenosylmethionine,S Adenosylmethionine Sulfate Tosylate
D014466	Ultraviolet Rays	That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.	Actinic Rays,Black Light, Ultraviolet,UV Light,UV Radiation,Ultra-Violet Rays,Ultraviolet Light,Ultraviolet Radiation,Actinic Ray,Light, UV,Light, Ultraviolet,Radiation, UV,Radiation, Ultraviolet,Ray, Actinic,Ray, Ultra-Violet,Ray, Ultraviolet,Ultra Violet Rays,Ultra-Violet Ray,Ultraviolet Black Light,Ultraviolet Black Lights,Ultraviolet Radiations,Ultraviolet Ray
D014616	Vaccinia virus	The type species of ORTHOPOXVIRUS, related to COWPOX VIRUS, but whose true origin is unknown. It has been used as a live vaccine against SMALLPOX. It is also used as a vector for inserting foreign DNA into animals. Rabbitpox virus is a subspecies of VACCINIA VIRUS.	Buffalopox virus,Poxvirus officinale,Rabbitpox virus,Buffalo Pox Virus,Rabbit Pox Virus,Buffalo Pox Viruses,Buffalopox viruses,Rabbit Pox Viruses,Rabbitpox viruses,Vaccinia viruses,Virus, Buffalo Pox,Viruses, Buffalo Pox,virus, Buffalopox
D014764	Viral Proteins	Proteins found in any species of virus.	Gene Products, Viral,Viral Gene Products,Viral Gene Proteins,Viral Protein,Protein, Viral,Proteins, Viral