Many Listeria species including L. monocytogenes contain the pathway for the biosynthesis of protocatechuate from shikimate and quinate. The qui1 and qui2 operons within these Listeria spp. encode enzymes for this pathway. The diversion of shikimate pathway intermediates in some Listeria species to produce protocatechuate suggests an important biological role for this compound to these organisms. A total of seven ORFs, including quiC2 , were identified within qui1 and qui2 , however only three proteins encoded by the operons have been functionally annotated. The final step in Listeria 's protocatechuate biosynthesis involves the conversion of dehydroshikimate by a dehydroshikimate dehydratase (DSD). In this study, we demonstrate that QuiC2 functions as a DSD in Listeria spp. through biochemical and structural analyses. Moreover, we show that QuiC2 forms a phylogenetic cluster distinct from other functionally annotated DSDs. The individual phylogenetic clusters of DSD are represented by enzymes that produce protocatechuate for distinct biological processes. Similarly, QuiC2 is expected to produce protocatechuate for a novel biological process. We postulate that protocatechuate produced by DSDs found within the QuiC2 phylogenetic cluster provides an ecological niche for representative organisms.

中文翻译：

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QuiC2代表在李斯特菌物种（包括单核细胞增生李斯特菌）中鉴定出的功能上不同的脱氢shi草酸酯脱水酶类别。

包括单核细胞增生李斯特菌在内的许多李斯特菌属物种都包含从sh草酸和奎宁酸生物合成原儿茶酸的途径。这些李斯特菌属菌种中的qui1和qui2操纵子。编码该途径的酶。某些李斯特菌属物种中iki草酸酯途径中间体的转移以产生原儿茶酸表明该化合物对这些生物体具有重要的生物学作用。在qui1和qui2内共鉴定出7个ORF，包括quiC2，但是仅对操纵子编码的3种蛋白质进行了功能注释。李斯特菌的最后一步的原儿茶酸生物合成涉及脱氢shi草酸酯脱水酶（DSD）转化脱氢shi草酸酯。在这项研究中，我们证明了QuiC2在李斯特菌属中充当DSD 。通过生化和结构分析。此外，我们表明QuiC2形成不同于其他功能注释的DSD的系统发生簇。DSD的各个系统发育簇均由产生用于不同生物过程的原儿茶酸的酶代表。同样，QuiC2有望为新的生物过程生产原儿茶酸。我们假设由QuiC2系统发生簇中发现的DSD产生的原儿茶酸为代表性生物提供了生态位。