As the second most abundant transition element and a crucial cofactor for many proteins, zinc is essential for the survival of all living organisms. To maintain required zinc levels and prevent toxic overload, cells and organisms have a collection of metal transport proteins for uptake and efflux of zinc. In bacteria, metal transport proteins are well defined for model organisms and many pathogens, but fewer studies have explored metal transport proteins, including those for zinc, in commensal bacteria from the gut microbiota. The healthy human gut microbiota comprises hundreds of species and among these, bacteria from the Lactobacillaceae family are well documented to have various beneficial effects on health. Furthermore, changes in dietary metal intake, such as for zinc and iron, are frequently correlated with changes in abundance of Lactobacillaceae. Few studies have explored zinc requirements and zinc homeostasis mechanisms in Lactobacillaceae, however. Here we applied a bioinformatics approach to identify and compare predicted zinc uptake and efflux proteins in several Lactobacillaceae genera of intestinal relevance. Few Lactobacillaceae had zinc transporters currently annotated in proteomes retrieved from the UniProt database, but protein sequence-based homology searches revealed that high-affinity ABC transporter genes are likely common, albeit with genus-specific domain features. P-type ATPase transporters are probably also common and some Lactobacillaceae genera code for predicted zinc efflux cation diffusion facilitators. This analysis confirms that Lactobacillaceae harbor genes for various zinc transporter homologs, and provides a foundation for systematic experimental studies to elucidate zinc homeostasis mechanisms in these bacteria.

中文翻译：

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肠道乳杆菌科锌转运蛋白的生物信息分析。

作为第二丰富的过渡元素和许多蛋白质的关键辅助因子，锌对于所有生物体的生存至关重要。为了维持所需的锌水平并防止毒性超载，细胞和生物体具有一系列金属转运蛋白来吸收和流出锌。在细菌中，模型生物和许多病原体的金属转运蛋白被明确定义，但很少有研究探索肠道微生物群共生细菌中的金属转运蛋白，包括锌的转运蛋白。健康的人类肠道微生物群由数百个物种组成，其中，乳杆菌科细菌已被充分证明对健康具有各种有益作用。此外，膳食金属摄入量的变化，例如锌和铁的摄入量，通常与乳杆菌丰度的变化相关。然而，很少有研究探讨乳杆菌科的锌需求和锌稳态机制。在这里，我们应用生物信息学方法来识别和比较几个与肠道相关的乳杆菌属中预测的锌摄取和流出蛋白。目前，从 UniProt 数据库检索到的蛋白质组中很少有乳杆菌科具有锌转运蛋白，但基于蛋白质序列的同源性搜索表明，高亲和力 ABC 转运蛋白基因可能很常见，尽管具有属特异性结构域特征。P 型 ATP 酶转运蛋白可能也很常见，一些乳杆菌科编码预测的锌流出阳离子扩散促进剂。该分析证实了乳杆菌科含有各种锌转运蛋白同源物的基因，并为阐明这些细菌中锌稳态​​机制的系统实验研究奠定了基础。