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| Type |
Poster Presentation |
| Area |
Life Chemistry |
| Room No. |
Exhibition Hall 2+3 |
| Time |
10월 19일 (목요일) 11:00~12:30 |
| Code |
BIO.P-286 |
| Subject |
Structural biochemistry of MccS and MccB in CxSAM-dependent production of a peptide antibiotic in Bacillus amyloliquefaciens |
| Authors |
Gyuhyeok Cho, Jungwook Kim*
Department of Chemistry, Gwangju Institute of Science and Technology, Korea
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| Abstract |
Microcin C (McC) is a ‘Trojan horse’ peptide antibiotic, encoded by six-gene mcc cluster in some strains of E. coli. Biosynthesis of McC initiates with the MccB-directed adenylation on the C-terminal asparagine of MccA, a heptapeptide precursor (MRTGNAN). Once mature McC is exported from producing cells and taken up by other sensitive cells, proteolysis results in the release of the non-peptide moiety, causing the inhibition of aspartyl-tRNA synthetase activity. A simpler form of mcc gene cluster was identified in Bacillus amyloliquefaciens, which consists of four genes. Unlike in E. coli, the N-terminal domain of MccB attaches cytosine at the C-terminal asparagine of MccA and the C-terminal domain of the MccB additionally modify cytosine moiety by carboxymethylation. B. amyloliquefaciens MccS, a homologue of E. coli, CmoA, synthesizes carboxy-S-adenosyl-L-methionine (cxSAM) which is the substrate of carboxymethylation, which inactivates the mechanism of resistance to McC in the sensitive cell. Here we present the X-ray crystal structure of MccS, demonstrating the structural diversity from that of E. coli CmoA. In addition, we have analyzed the in vitro activity of bifunctional MccB, the second instance of the use of CxSAM in living cells. Our studies support the hypothesis that biological use of CxSAM may be widespread, not just confined in tRNA modification. |
| E-mail |
gyuhyeokcho@gist.ac.kr |
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120th General Meeting of the KCS