Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/21190
標題: 枯草桿菌 (Bacillus subtilis) 中豐原素合成基因的研究
Analysis of the Genes Encoding the Biosynthesis of Fengycin in Bacillus subtilis F29-3
作者: 陳奇良
Chen, Chyi-Liang
關鍵字: Bacillus subtilis;枯草桿菌;Fengycin;Antifungal antibiotic;Lipopeptide antibiotic;豐原素;抗真菌之抗生素;脂胜呔抗生素
出版社: 植物學系
摘要: 
枯草桿菌F29-3為革蘭氏陽性菌,好氧,具游動性,菌體呈桿狀並能產生孢子
以及對抗絲狀真菌的抗生素,豐原素(fengycin).利用轉位子Tn917之突變
作用,總共獲得20株不生產豐原素的突變株.這20株突變基因經選殖,限制
脢圖譜及DNA序列之分析,而被歸類為11種.利用其中一個突變基因(pBTS7)
的序列作為探針,足構築於pHC79中的枯草桿菌F29-3的cosmid基因庫中篩
選得一選殖株,名為pFC660.分析並比較pFC660與所選殖的11種突變基因的
限制脢圖譜以及Southern hybridization的結果,發現有8種突變株的
Tn917所插入的位置在pFC660內.這些突變基因的序列與 GenBank的DNA序
列比較後,發現有4種突變基因與一些胜呔合成脢有很高的相似性.另外有4
種突變基因與脂肪酸的生合成及代謝有關的基因相類似.經DNA序列的分
析,發現pFC660之B2區域的全長為11,459 bp, 其中含有一不完整的基因,''
fenA,及一個完整的基因,fenB.FenB蛋白的大小為 143.6 kDa,與一些胜呔
合成脢的胺基酸結合區有21.0-46.2%的相似度,而 ''FenA蛋白的大小
為227.1-kDa. '

Bacillus subtilis F29-3 is a gram-positve, rod-shaped,aerobic,
spore-forming, motile bacterium. This organism is known to
produce an antifungal antibiotic, fengycin. A total of twenty
B. subtilis F29-3 mutants defective in fengycin bio- synthesis
was obtained by Tn917 mutagenesis. Those sequence flanking the
Tn917 insertion site in these twenty mutants were cloned,
mapped and sequenced. Results showed that Tn917 was inserted
in eleven different locations on the chromosome. One of the
clones, pBTS7, was selected and used as a probe to screen for
genes encoding fengycin biosynthesis in a cosmid library
established with pHC79. A clone, pFC660 which hybridized to the
probe, was selected. Mapping study revealed that eight mutants
had insertion within the DNA fragment cloned in pFC660. Among
them, four had Tn917 inserted in regions which encoded peptide
sequences similar to part of peptide synthetases. Another four
mutants had Tn917 inserted in the regions encoding the peptide
sequences that were similar to part of the enzymes required for
lipid synthesis. The 12-kb BamHI fragment of pFC660 was
sequences. The length of this fragment was 11,459 bp long.
This fragment contains a 3,825-bp peptide synthetase gene, fenB
which encodes a protein of 143.6-kDa with 21.0-46.2% similarity
to the amino acid-binding domains of different peptide
synthetases. The 12-kb BamHI fragment also contains an
incomplete open reading frame, ''fenA, which encodes a peptide
synthetase of 227.1 kDa. Protein analysis revealed that fenB
indeed encodes a 143-kDa protein and intact fenA may encode a
protein of approximately 500 kDa. The results obtained from
this dissertation suggest that a large number of genes in B.
subtilis F29-3 is involved in fengycin biosynthesis.
URI: http://hdl.handle.net/11455/21190
Appears in Collections:生命科學系所

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