• Journal of Plant Biology
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• v.32 no.4
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• pp.331-341
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• 1989

DNA methyltransferase was purified 282.6-fold from Chlamydomonas reinhardtii 21gr (mt+) gametic cell to examine the effect of polyamine on the enzyme acctivity. Polyacrylamide gel electrophoresis(PAGE) revealed at least three bands(1 major band, 2 minor bands). Among these, the major band represents DNA methyltransferase. Polyacrylamide gel electrophoresis in the presence of 0.1% sodium dodecylsulfate(SDS-PAGE) revealed a major band with M.W. 60,000. DNA methyltransferase activity was inhibited more effectively by spermine than by spermidine, and the inhibition by putrescine was smaller than spermine and spermidine. DNA methyltransferase activity was inhibited by 40% and 53% at 5mM and 20mM spermine, respectively. In the case of spermidine, the inhibition was 35% at 10mM and 44% at 20mM. However, the inhibition by putrescine appeared only above 5mM and reached about 25% at 20mM.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.941-946
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• 2007

Bacillus halodurans O-methyltransferase (BhOMT) is a S-adenosylmethionine (SAM or AdoMet) dependent methyltransferase. Three dimensional structure of the BhOMT bound to S-adenosyl-L-homocysteine (SAH or AdoHcy) has been determined by comparative homology modeling. BhOMT has 40% sequence identity with caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) from alfalfa. Based on x-ray structure of CCoAOMT, three dimensional structure of BhOMT was determined using MODELLER. The substrate binding sites of these two proteins showed slight differences, but these differences were important to characterize the substrate of BhOMT. Automated docking study showed that four flavonoids, quercetin, fisetin, myricetin, and luteolin which have two hydroxyl groups simultaneously at 3'- and 4'-position in the B-ring and structural rigidity of Cring resulting from the double bond characters between C2 and C3, were well docked as ligands of BhOMT. These flavonoids form stable hydrogen bondings with K211, R170, and hydroxyl group at 3'-position in the Bring has stable electrostatic interaction with Ca2+ ion in BhOMT. This study will be helpful to understand the biochemical function of BhOMT as an O-methyltransferase for flavonoids.

• Applied Biological Chemistry
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• v.45 no.4
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• pp.203-206
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• 2002

${\gamma}-Tocopherol$ methyltransferase (TMT) is an enzyme catalyzing ${\gamma}-tocopherol$ into ${\alpha}-tocopherol$ at the final step of ${\alpha}-tocopherol$ synthesis pathway. Putative TMT cDNA clone specific to Perilla frutescens immature seeds was isolated from cDNA library. The cDNA clone consisted of 1369 bp open reading frame encoding 369 amino acids with a relative Mw of 42 kDa. Results revealed the CDNA has 60% homology to Arabidopsis thaliana TMT, and possesses methyltransferase and S-adenosyl methionine-binding domains, suggesting that cDNA encodes a ${\gamma}-tocopherol$ methyltransferase To characterize the properties of the TMT gene, the cDNA sequences coding for mature TMT were expressed in E. coli and assayed to determine the enzyme activity in vitro.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.262-262
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• 1994

Ras oncogene의 산물로서 대부분의 암조직이나 transformed human cell에서 거의 공통적으로 발견되는 p21 단백질은 C-terminal processing에 의해 먼저 C-terminal cysyeine에 palmition 된 후 carboxylmethylation 된다. Palmitation은 transforming activity의 요건인 세포막에 대한 친화력을 유지시키기 위한것으로 추측되며, cysteine residue의 carboxylmethylation의 의미는 아직 확실히 밝혀지고 있지 않으나 세포막에 대한 친화력을 증가 시키는 것으로 추측되고있다. 본 연구에서는 S-Farnesylcysteine Methyltransferase의 기질로서 N-acetyl-S-trans, trans-farnesyl-L-cysteine(AFC)을 합성하였으며, 본 실험실에서 계속 연구하여 온 돼지 간장으로 부터 정제한 천연 단백성 Methylation Inhibitor의 S-Farnesylcysteine Methyltransferase 활성에 대한 억제효과를 검색하였다. 천연 단백성 Methylation Inhibitor는 돼지 간조직의 soluble fraction을 열처리하여 Sephadex G-25 column chromatngraphy한 후 reverse phase HPLC로 정제하였다. 본 inhibitor는 약 10개의 아미노산으로 구성된 peptide성 천연물질로 분자량은 1,400 Da 으로서 합성한 AFC를 기질로 하였을 때, 흰쥐 뇌 조직내 S-Farnesylcysteine methyltransferase에 대한 $IC_{50}$/은 0,82 $\times$ $10^{-6}$ M이었으며 또한 human cancer cell line의 S-Farnesylcysteine Methyltransferase에 대해서도 현저한 저해효과를 나타내었다.

• The Korean Journal of Mycology
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• v.43 no.1
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• pp.33-39
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• 2015

In filamentous fungi, velvet complex associated with the veA gene plays pivotal roles in development and secondary metabolism. In a model fungus Aspergillus nidulans, many proteins that can interact with VeA, including two methyltransferases VipB and VipC, have been isolated and characterized. In this study, we isolated homologs of the vipB and vipC genes in the human opportunistic pathogenic fungus Aspergillus fumigatus and named AfuvipB and AfuvipC. The AfuvipB gene, annotated as Afu3g14920 in the Aspergillus Genome Database (AspGD) database, consists of 1,510 bp interrupted with 10 introns yielding 336 amino acid-long putative methyltransferase protein. Similarly, AfuvipC, which is Afu8g01930, has 10 introns and encodes a polypeptide with 339 amino acids having a methyltransferase domain in the middle of the protein. To characterize the function of the genes in A. fumigatus, knock-out mutants were generated and the phenotypes were observed. Deletion of AfuvipB gene caused no obvious phenotypic change on point inoculation but showed smaller colony than wild-type when the mutant was subjected to culture on single spore-driven culture condition. However, AfuvipC deletion mutant demonstrated no phenotypic difference from wild type both in point inoculation and streaking cultures. These results indicate that the two methyltransfereases might have a redundant role and could be dispensable in normal culture conditions.

• The Korean Journal of Mycology
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• v.21 no.4
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• pp.279-284
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• 1993

The metE gene coding for $N^{5}-methyl-H_{4}-folate;$ homocysteine methyltransferase from the basidiomycete Ganoderma lucidum was cloned by complementation of methionine-requiring mutants of E. coli. The size of a inserted DNA was about 1.54 kb and had 5 restriction enzyme sites. A physical map was constructed. Southern blot analysis confirmed the presence of a transforming DNA in the genome of Ganoderma lucidum. indicating the presence of a single copy.

• International Journal of Oral Biology
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• v.31 no.3
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• pp.81-86
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• 2006

SET (Suppressor of variegation, Enhancer of zeste, and the Trithorax) domain-containing proteins are known to have methyltransferase activity at lysine residues of histone proteins. In this study, we identified a novel SET domain-containing protein from mouse and named Kodo7. Indeed, Kodo7 has methyltransferase activity at K9 residue of the H3 protein as demonstrated by a histone methyl-transferse activity assay using GST-tagged Kodo7. Confocal microscopy showed that Kodo7 is co-localized with histones in the nucleus. Interestingly, ectopic expression of Kodo7 by transient transfection induced cell death and treatment of the transfectants with a caspase-3 inhibitor, Ac-DEVD-AFC decreased Kodo7-induced apoptosis. These results suggest that Kodo7 induces apoptotic cell death through increased methylation of histones leading to transcriptional repression.

• Archives of Pharmacal Research
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• v.17 no.5
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• pp.354-359
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• 1994

The activity of SD-framesylcysteine O-methyltransferase was assayed by incubating the enzyrne with a synthetic in vitro substrate, [N-acetyl-S-trans, trns-famesyl-L-cysteine (AFC)], together with S-adenosyl-L-[emthyl-$_{14}$C)ester(AFCME)], was then analyzed either directly on HPLC or by converting the AFC[$methyl^{14}C$]ME to [$methyl^{14}C$] aclcohol by basehydrolysis. Employing these two analytical methods, it was established that a peptide purifed from rat liver cytosol fraction [Int. J. Biochem., 25, 1157 919930] strongly inhibited the above enzyme activity with $IC_{50}\; of\; 7.1\times 10^{-8}$ M. Also, the S-famesylcysteine O-methyltransferase from several human colon cancer cells was equally inhibited by the peptide.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.2
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• pp.87-94
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• 2003

Recently, many researches for plant alkaloids, one of the largest groups of natural products, are reported because of their various pharmacological activity. This study was carried out to clone putrescine N-methyltransferase (PMT) gene which is a key enzyme in diverting polyamine metabolism towards the biosynthesis of nicotine and related alkaloids from Burley tobacco. To induce expression of PMT gene in tobacco plant, the floral meristem was removed and then mRNA was purified from root. cDNA encoding PMT gene was isolated by RT PCR and cloned. Three different groups of clones were screened by PCR and restriction enzyme digestion analysis and were characterized. The data of these screening revealed that three types of PMT are present in Burley tobacco. Comparison of the nucleotide sequence of this three genes encoding putative PMT with those of other tobaccos revealed that two types of PMT are newly discovered from Nicotiana tabacum cv. Br21 tobacco and they were same as PMT2, PMT3 of N. tabacum cv. Xanthi.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.1
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• pp.12-19
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• 2003

Transgenic tobacco plants were selected by using the transformation of putrescine N-methyltransferase(PMT) gene, the key enzyme in diverting polyamine metabolism towards the biosynthesis of nicotine. PMT was fused in reverse orientation to the CaMV 35S promoter of the plant expression vector pBTEX(pPAB3) to produce tobacco plants of low nicotine content. To compare nicotine content, only pBTEX vector and PMT gene which was fused in forward orientation to the CaMV 35S promoter(pPAB2) were also transformed to the leaf tobacco plants(Nicotiana tabacum cv. NC82 and N. tabacum cv. Br2l). The presence of sense- and antisense-PMT gene, and pBTEX vector in the transgenic plant was confirmed by genomic PCR.