Department of Chemistry and Biochemistry University of California, Santa Barbara, CA 93106 United States.
Department of Biology and Chemistry, University of Bremen, and Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Germany.
J Inorg Biochem. 2021 Aug;221:111457. doi: 10.1016/j.jinorgbio.2021.111457. Epub 2021 Apr 20.
It is well known that bacteria and fungi have evolved sophisticated systems for acquiring the abundant but biologically inaccessible trace element iron. These systems are based on high affinity Fe(III)-specific binding compounds called siderophores which function to acquire, transport, and process this essential metal ion. Many hundreds of siderophores are now known and their numbers continue to grow. Extensive studies of their isolation, structure, transport, and molecular genetics have been undertaken in the last three decades and have been comprehensively reviewed many times. In this review we focus on a unique subset of siderophores that has only been recognized in the last 20 years, namely those whose iron complexes display photoactivity. This photoactivity, which typically results in the photooxidation of the siderophore ligand with concomitant reduction of Fe(III) to Fe(II), seemingly upsets the siderophore paradigm of forming and transporting only extremely stable Fe(III) complexes into microbial cells. Here we review their structure, synthesis, photochemistry, photoproduct coordination chemistry and explore the potential biological and ecological consequences of this photoactivity.
众所周知，细菌和真菌已经进化出复杂的系统来获取丰富但生物上无法获得的痕量元素铁。这些系统基于高亲和力的 Fe(III)-特异性结合化合物，称为铁载体，其功能是获取、运输和处理这种必需的金属离子。目前已知有数百种铁载体，并且它们的数量还在不断增加。在过去的三十年中，对它们的分离、结构、运输和分子遗传学进行了广泛的研究，并多次进行了全面的综述。在这篇综述中，我们专注于铁载体的一个独特子集，这个子集仅在过去 20 年才被认识到，即那些其铁配合物具有光活性的铁载体。这种光活性通常导致铁载体配体的光氧化，同时将 Fe(III)还原为 Fe(II)，这似乎颠覆了铁载体形成和运输仅极稳定的 Fe(III)配合物进入微生物细胞的范例。在这里，我们综述了它们的结构、合成、光化学、光产物配位化学，并探讨了这种光活性的潜在生物学和生态学后果。
