Lowe Phillip T, Lüddecke Isabeau, O'Hagan David
School of Chemistry and Biomedical Sciences Research Centre, University of St Andrews, North Haugh, KY16 9ST, St Andrews, UK.
Chembiochem. 2025 Jan 2;26(1):e202400861. doi: 10.1002/cbic.202400861. Epub 2024 Nov 25.
The fluorinase enzyme (EC 2.5.1.63) utilises fluoride ion and S-adenosyl-L-methionine (SAM) as substrates for conversion to 5'-fluoro-5'-deoxy-adenosine (5'-FDA) and L-methionine (L-Met). The enzyme has a very strict substrate specificity, however it has been shown to tolerate acetylenes and NH replacements for H at C-2 of the adenine ring of SAM. This substrate tolerance is explored further here with -NHR, -N, -OR and -SR substituents attached to C-2. New activities are demonstrated, for example with NH-methyl, NH-propyl,NH-butyl and O-butyl substrates at C-2, however azide and thioethers were not tolerated. Outcomes are supported by in silico analysis, revealing favourable H-bonding interactions involving NH and O substituents at the adenine C-2 position with N278 and the backbone amide of A279 at the active site respectively. The study informs on the selectivity of the fluorinase as a tool for radiolabelling candidate ligands with fluorine-18 for positron emission tomography programmes.
氟化酶（EC 2.5.1.63）利用氟离子和S-腺苷-L-甲硫氨酸（SAM）作为底物，将其转化为5'-氟-5'-脱氧腺苷（5'-FDA）和L-甲硫氨酸（L-Met）。该酶具有非常严格的底物特异性，然而研究表明它能够耐受乙炔以及SAM腺嘌呤环C-2位上H被NH取代的情况。本文进一步探索了C-2位连接有-NHR、-N、-OR和-SR取代基时该酶对底物的耐受性。研究发现了一些新的活性，例如C-2位上的NH-甲基、NH-丙基、NH-丁基和O-丁基底物，但叠氮化物和硫醚则不能被耐受。计算机模拟分析支持了这些结果，揭示了腺嘌呤C-2位上的NH和O取代基分别与活性位点处的N278和A279主链酰胺形成了有利的氢键相互作用。该研究为氟化酶作为一种用氟-18对候选配体进行放射性标记以用于正电子发射断层扫描项目的工具的选择性提供了信息。
