Purification and biochemical characterization of mutacin I from the group I strain of Streptococcus mutans, CH43, and genetic analysis of mutacin I biosynthesis genes
Purification and biochemical characterization of mutacin I from the group I strain of Streptococcus mutans, CH43, and genetic analysis of mutacin I biosynthesis genes
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DOI：
10.1128/aem.66.8.3221-3229.2000
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发表时间：
2000-08-01
影响因子：
4.4
通讯作者：
Caufield, PW
中科院分区：
文献类型：
--
作者：
Qi, FX;Chen, P;Caufield, PW
之前，我们报道了突变蛋白 III 的分离和表征：以及来自变形链球菌 III 组菌株 UA787 的突变蛋白 III 生物合成基因的遗传分析（F. Qi, P. Chen 和 P. W. Caufield, Appl. Environ. Microbiol. 65:3880-3887, 1999）。在分离 mutacin III 结构基因的同一过程中，我们还克隆了 mutacin I 的结构基因。在本报告中，我们介绍了来自 I 组菌株 CH43 的 mutacin I 的纯化和生化特征，并比较了 mutacin I 和 mutacin III 生物合成基因。突变蛋白 I 生物合成基因座由 14 个基因组成，顺序为 mutR、-A、-A'、-B、C、-D、-P、-T、-F、-E、-G、orfX、orfY、orfZ。 mutA 是 mutacin I 的结构基因，而 mutA' 不是 mutacin I 活性所必需的。 DNA 和蛋白质序列分析表明，mutacins I 和 In 彼此同源，可能来自共同的祖先。成熟的突变蛋白 I 大小为 24 个氨基酸，分子量为 2,364 Da。 Mutacin I 的乙硫醇修饰和肽测序表明它含有六个脱水丝氨酸，其中四个可能与硫醚桥的形成有关。突变蛋白 I 的一级序列与突变蛋白 III 和表皮蛋白的一级序列的比较表明，突变蛋白 I 可能具有与表皮蛋白相同的桥接模式。
Previously, we reported isolation and characterization of mutacin III: and genetic analysis of mutacin III biosynthesis genes from the group III strain of Streptococcus mutans, UA787 (F. Qi, P. Chen, and P. W. Caufield, Appl. Environ. Microbiol. 65:3880-3887, 1999). During the same process laf isolating the mutacin III structural gene, we also cloned the structural gene for mutacin I. In this report, we present purification and biochemical characterization of mutacin I from the group I strain CH43 and compare mutacin I and mutacin III biosynthesis genes. The mutacin I biosynthesis gene locus consists of 14 genes in the order mutR, -A, -A', -B, C, -D, -P, -T, -F, -E, -G, orfX, orfY, orfZ. mutA is the structural gene for mutacin I, while mutA' is not required for mutacin I activity. DNA and protein sequence analysis revealed that mutacins I and In are homologous to each other, possibly arising from a common ancestor. The mature mutacin I is 24 amino acids in size and has a molecular mass of 2,364 Da. Ethanethiol modification and peptide sequencing of mutacin I revealed that it contains six dehydrated serines, four of which are probably involved with thioether bridge formation. Comparison of the primary sequence of mutacin I with that of mutacin III and epidermin suggests that mutacin I likely has the same bridging pattern as epidermin.