Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India.
Life Science, Homi Bhabha National Institute (DAE-Deemed University), Mumbai, Maharashtra, India.
Microbiol Spectr. 2022 Dec 21;10(6):e0347022. doi: 10.1128/spectrum.03470-22. Epub 2022 Dec 1.
Environmental DNA uptake by certain bacteria and its integration into their genome create genetic diversity and new phenotypes. DNA processing protein A (DprA) is part of a multiprotein complex and facilitates the natural transformation (NT) phenotype in most bacteria. Deinococcus radiodurans, an extremely radioresistant bacterium, is efficient in NT, and its genome encodes nearly all of the components of the natural competence complex. Here, we have characterized the DprA protein of this bacterium (DrDprA) for the known characteristics of DprA proteins of other bacteria and the mechanisms underlying the DNA-RecA interaction. DrDprA has three domains. studies showed that purified recombinant DrDprA binds to both single-strand DNA (ssDNA) and double-strand DNA (dsDNA) and is able to protect ssDNA from nucleolytic degradation. DrDprA showed a strong interaction with DrRecA and facilitated RecA-catalyzed functions . Mutational studies identified DrDprA amino acid residues crucial for oligomerization, the interaction with DrRecA, and DNA binding. Furthermore, we showed that both oligomerization and DNA binding properties of DrDprA are integral to its support of the DrRecA-catalyzed strand exchange reaction (SER) . Together, these data suggested that DrDprA is largely structurally conserved with other DprA homologs but shows some unique structure-function features like the existence of an additional C-terminal Drosophila melanogaster Miasto-like protein 1 (DML1) domain, equal affinities for ssDNA and dsDNA, and the collective roles of oligomerization and DNA binding properties in supporting DrRecA functions. Bacteria can take up extracellular DNA (eDNA) by natural transformation (NT). Many bacteria, including Deinococcus radiodurans, have constitutive competence systems and can take up eDNA throughout their growth phase. DprA (DNA processing protein A) is a transformation-specific recombination mediator protein (RMP) that plays a role in bacterial NT, and the absence of this gene significantly reduces the transformation efficiencies of both chromosomal and plasmid DNA. NT helps bacteria survive under adverse conditions and contributes to genetic diversity in bacteria. The present work describes the characterization of DprA from D. radiodurans and will add to the existing knowledge of DprA biology.
某些细菌可以通过环境 DNA 摄取并将其整合到基因组中，从而产生遗传多样性和新的表型。DNA 加工蛋白 A（DprA）是多蛋白复合物的一部分，可促进大多数细菌的自然转化（NT）表型。耐辐射球菌是一种具有极强辐射抗性的细菌，其 NT 效率很高，其基因组编码了自然感受态复合物的几乎所有成分。在这里，我们对该细菌的 DprA 蛋白（DrDprA）进行了表征，以了解其他细菌的 DprA 蛋白的已知特征以及 DNA-RecA 相互作用的机制。DrDprA 具有三个结构域。研究表明，纯化的重组 DrDprA 可以结合单链 DNA（ssDNA）和双链 DNA（dsDNA），并能够保护 ssDNA 免受核酸酶降解。DrDprA 与 DrRecA 表现出强烈的相互作用，并促进 RecA 催化的功能。突变研究确定了 DrDprA 对寡聚化、与 DrRecA 的相互作用以及 DNA 结合至关重要的氨基酸残基。此外，我们还表明，DrDprA 的寡聚化和 DNA 结合特性对于支持 DrRecA 催化的链交换反应（SER）至关重要。这些数据表明，DrDprA 在很大程度上与其他 DprA 同源物在结构上是保守的，但表现出一些独特的结构-功能特征，例如存在额外的 Drosophila melanogaster Miasto-like protein 1（DML1）结构域、对 ssDNA 和 dsDNA 的相等亲和力以及寡聚化和 DNA 结合特性在支持 DrRecA 功能方面的集体作用。细菌可以通过自然转化（NT）摄取细胞外 DNA（eDNA）。许多细菌，包括耐辐射球菌，都具有组成型感受态系统，可以在整个生长阶段摄取 eDNA。DprA（DNA 加工蛋白 A）是一种转化特异性重组介体蛋白（RMP），在细菌 NT 中起作用，该基因的缺失会显著降低染色体和质粒 DNA 的转化效率。NT 有助于细菌在不利条件下生存，并有助于细菌的遗传多样性。本工作描述了耐辐射球菌 DprA 的表征，将为 DprA 生物学的现有知识增添新内容。
