Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom.
Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom.
Acta Crystallogr D Struct Biol. 2023 Aug 1;79(Pt 8):694-705. doi: 10.1107/S2059798323004473. Epub 2023 Jul 10.
Siderophore-binding proteins from two thermophilic bacteria, Geobacillus stearothermophilus and Parageobacillus thermoglucosidasius, were identified from a search of sequence databases, cloned and overexpressed. They are homologues of the well characterized protein CjCeuE from Campylobacter jejuni. The iron-binding histidine and tyrosine residues are conserved in both thermophiles. Crystal structures were determined of the apo proteins and of their complexes with iron(III)-azotochelin and its analogue iron(III)-5-LICAM. The thermostability of both homologues was shown to be about 20°C higher than that of CjCeuE. Similarly, the tolerance of the homologues to the organic solvent dimethylformamide (DMF) was enhanced, as reflected by the respective binding constants for these ligands measured in aqueous buffer at pH 7.5 in the absence and presence of 10% and 20% DMF. Consequently, these thermophilic homologues offer advantages in the development of artificial metalloenzymes using the CeuE family.
从嗜热细菌（如 Geobacillus stearothermophilus 和 Parageobacillus thermoglucosidasius）的序列数据库中搜索到了铁载体结合蛋白，并对其进行了克隆和过表达。这些蛋白与 Campylobacter jejuni 中的典型蛋白 CjCeuE 同源。在两种嗜热菌中，铁结合的组氨酸和酪氨酸残基均保守。确定了这些蛋白的apo 形式及其与铁（III）-氮氧螯合素及其类似物铁（III）-5-LICAM 的复合物的晶体结构。结果表明，两种同源物的热稳定性均比 CjCeuE 高约 20°C。同样，这些同源物对有机溶剂二甲基甲酰胺（DMF）的耐受性增强，这反映在各自在 pH 7.5 的水性缓冲液中测量的这些配体的结合常数，在不存在和存在 10%和 20% DMF 的情况下。因此，这些嗜热同源物在使用 CeuE 家族开发人工金属酶方面具有优势。
