Ma Amy T, Kantner Daniel S, Beld Joris
Department of Microbiology and Immunology, Center for Advanced Microbial Processing, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States.
Department of Microbiology and Immunology, Center for Advanced Microbial Processing, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States.
Vitam Horm. 2022;119:43-63. doi: 10.1016/bs.vh.2022.01.004. Epub 2022 Mar 1.
Cobamides are a family of structurally-diverse cofactors which includes vitamin B and over a dozen natural analogs. Within the nucleotide loop structure, cobamide analogs have variable lower ligands that fall into three categories: benzimidazoles, purines, and phenols. The range of cobamide analogs that can be utilized by an organism is dependent on the specificity of its cobamide-dependent enzymes, and most bacteria are able to utilize multiple analogs but not all. Some bacteria have pathways for cobamide remodeling, a process in which imported cobamides are converted into compatible analogs. Here we discuss cobamide analog diversity and three pathways for cobamide remodeling, mediated by amidohydrolase CbiZ, phosphodiesterase CbiR, and some homologs of cobamide synthase CobS. Remodeling proteins exhibit varying degrees of specificity for cobamide substrates, reflecting different strategies to ensure that imported cobamides can be utilized.
钴胺素是一类结构多样的辅因子，包括维生素B和十几种天然类似物。在核苷酸环结构中，钴胺素类似物具有可变的低级配体，可分为三类：苯并咪唑、嘌呤和酚类。生物体能够利用的钴胺素类似物范围取决于其钴胺素依赖性酶的特异性，大多数细菌能够利用多种类似物，但并非全部。一些细菌具有钴胺素重塑途径，在这个过程中，导入的钴胺素被转化为兼容的类似物。在这里，我们讨论钴胺素类似物的多样性以及由酰胺水解酶CbiZ、磷酸二酯酶CbiR和钴胺素合酶CobS的一些同源物介导的三种钴胺素重塑途径。重塑蛋白对钴胺素底物表现出不同程度的特异性，反映了确保导入的钴胺素能够被利用的不同策略。
