CLONING, SEQUENCING, AND MOLECULAR ANALYSIS OF THE SOL OPERON OF CLOSTRIDIUM-ACETOBUTYLICUM, A CHROMOSOMAL LOCUS INVOLVED IN SOLVENTOGENESIS
CLONING, SEQUENCING, AND MOLECULAR ANALYSIS OF THE SOL OPERON OF CLOSTRIDIUM-ACETOBUTYLICUM, A CHROMOSOMAL LOCUS INVOLVED IN SOLVENTOGENESIS
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DOI：
10.1128/jb.175.21.6959-6969.1993
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发表时间：
1993-11-01
影响因子：
3.2
通讯作者：
DURRE, P
中科院分区：
文献类型：
--
作者：
FISCHER, RJ;HELMS, J;DURRE, P
乙酰丁酸梭菌的一个与ADC操纵子相邻的DNA区域已经被克隆和测序。编码乙酰乙酰辅酶A：乙酸酯/丁酸：辅酶A转移酶(ctfB和ctfA)和乙醇/乙醛脱氢酶(Adhe)的结构基因被鉴定出来。这三个基因与一个功能未知的小开放阅读框(ORF)(adhe的上游)一起形成了一个操纵子(Sol操纵子)，mRNA分析表明。完整的Sol操纵子在溶剂化开始之前被转录诱导或去抑制，从而证实了早期Northern与ctfB基因探针(U.Gerischer和P.Durre，J.细菌)杂交的结果。174：426-433,1992)。在Sol操纵子的上游，我们发现了两个推定的启动子，它们位于可能由几个反向重复形成的茎环结构的区域。远端启动子P1在溶剂型C乙酰丁酸菌细胞中仅有少量转录启动，但在大肠杆菌中被识别，可能是因为它与sigma70共同序列高度相似。在溶剂型C-乙酰丁酸菌中，近端启动子P2是主要的转录起始点，但在大肠杆菌中不被识别。梭状芽胞杆菌的ADE与一个新的酒精脱氢酶家族(III型)有很高的相似性。在克隆的DNA区域还发现了另外两个ORF(ORF 5和ORF 6)，与各种现有数据库中的序列没有明显的相似性。MRNA研究表明，ORF 5形成单顺反子操纵子，并在溶质形成开始之前表达增加。
A DNA region of Clostridium acetobutylicum contiguous with the adc operon has been cloned and sequenced. Structural genes encoding the acetoacetyl coenzyme A:acetate/butyrate:coenzyme A transferase (ctfB and ctfA) and an alcohol/aldehyde dehydrogenase (adhE) could be identified. These three genes together with a small open reading frame (ORF) of unknown function (upstream of adhE) formed an operon (sol operon), as shown by mRNA analyses. The complete sol operon was transcriptionally induced or derepressed before the onset of solventogenesis, thus confirming earlier results of Northern hybridizations with a ctfB gene probe (U. Gerischer and P. Durre, J. Bacteriol. 174:426-433, 1992). Upstream of the sol operon, we identified two putative promoters that were located in regions with possible stem-loop structures formed by several inverted repeats. The distal promoter P1 showed only minor transcription initiation in solventogenic C acetobutylicum cells but was recognized in Escherichia coli, presumably because of its high similarity to the sigma70 consensus sequence. The adhE-proximal promoter P2 directed the major transcription start point in solventogenic C acetobutylicum but was not recognized in E. coli. The clostridial AdhE showed high similarity to a novel family (type III) of alcohol dehydrogenases. Two other ORFs (ORF 5 and ORF 6) were found on the cloned DNA region that showed no significant similarity to sequences in various available data bases. mRNA studies revealed that ORF 5 formed a monocistronic operon and showed increased expression before onset of solventogenesis.