THE GENES INVOLVED IN PRODUCTION OF AND IMMUNITY TO SAKACIN-A, A BACTERIOCIN FROM LACTOBACILLUS-SAKE LB706
THE GENES INVOLVED IN PRODUCTION OF AND IMMUNITY TO SAKACIN-A, A BACTERIOCIN FROM LACTOBACILLUS-SAKE LB706
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DOI：
10.1128/jb.177.8.2125-2137.1995
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发表时间：
1995-04-01
影响因子：
3.2
通讯作者：
HOLCK, A
中科院分区：
文献类型：
--
作者：
AXELSSON, L;HOLCK, A
沙卡菌素A是由清酒乳杆菌Lb706产生的一种小型、耐热、抗李氏杆菌细菌素。测定了一个8,668个核苷酸片段的核苷酸序列，该片段包含生产和免疫所需的所有信息。序列显示存在两个不同转录的操纵子。第一个包括结构基因Sapa(以前被命名为Saka)和SaA，它编码一个由90个氨基酸残基组成的推定多肽。第二个包括SapK(以前被命名为sakB)、SAPR、SAPT和SAPR，SapK和SAPR可能编码一个组氨酸激酶和一个反应调节因子，与AGRB/AGRA型两组分信号转导系统有显著的相似之处，推测的SAPT和SAPE蛋白有相似之处，即大肠杆菌溶血素A样信号，序列独立的运输系统，SAPT是HlyB类似物，与细菌的ATP结合盒出口蛋白同源，参与细菌的运输。移码突变和缺失分析表明，SapK和SAPR是生产和免疫所必需的，而SAPT和Sape是生产所必需的，但不是免疫所必需的。SAIA多肽可能参与了对SAKA的免疫。操纵子之间的区域含有新近发现的酒糟插入元件IS1163，IS1163似乎不参与sap基因的表达。Northern(RNA)印迹分析表明，可能的SapK/SAPR系统可能在这两个操纵子上发挥转录激活作用。SapA启动子上游的35bp序列和SapK上游的相似序列(35个核苷酸中有30个相同)是正确表达所必需的，因此可能是转录激活的靶标。
Sakacin A is a small, heat-stable, antilisterial bacteriocin produced by Lactobacillus sake Lb706. The nucleotide sequence of a 8,668-bp fragment, shown to contain all information necessary for sakacin A production and immunity, was determined. The sequence revealed the presence of two divergently transcribed operons. The first encompassed the structural gene sapA (previously designated sakA) and saiA, which encoded a putative peptide of 90 amino acid residues. The second encompassed sapK (previously designated sakB), sapR, sapT, and sapE, sapK and sapR presumably encoded a histidine kinase and a response regulator with marked similarities to the AgrB/AgrA type of two-component signal-transducing systems, The putative SapT and SapE proteins shared similarity,vith the Escherichia coli hemolysin A-like signal, sequence-independent transport systems, SapT was the HlyB analog with homology to bacterial ATP-binding cassette exporters implicated in bacteriocin transport. Frameshift mutations and deletion analyses showed that sapK and sapR were necessary for both production and immunity, whereas sapT and sapE were necessary for production but not for immunity. The putative SaiA peptide was shown to be involved in the immunity to sakacin A. The region between the operons contained IS1163, a recently described L. sake insertion element, IS1163 did not appear to be involved in expression of the sap genes, Northern (RNA) blot analysis revealed that the putative SapK/SapR system probably acts as a transcriptional activator on both operons. A 35-bp sequence, present upstream of the putative sapA promoter, and a similar sequence (30 of 35 nucleotides identical) upstream of sapK were shown to be necessary for proper expression and could thus be possible targets for transcriptional activation.