Long-chain fatty acyl-CoA synthetases (ACSLs) are homologues of firefly luciferase but are incapable of emitting light with firefly luciferin. Recently, we found that an ACSL from the fruit fly Drosophila melanogaster is a latent luciferase that will emit light with the synthetic luciferin CycLuc2. Here, we have profiled a panel of three insect ACSLs with a palette of >20 luciferin analogues. An ACSL from the nonluminescent beetle Agrypnus binodulus (AbLL) was found to be a second latent luciferase with distinct substrate specificity. Several rigid luciferins emit light with both ACSLs, but styryl luciferin analogues are light-emitting substrates only for AbLL. On the other hand, an ACSL from the luminescent beetle Pyrophorus angustus lacks luciferase activity with all tested analogues, despite its higher homology to beetle luciferases. Further study of ACSLs is expected to shed light on the features necessary for bioluminescence and substrate selectivity.

中文翻译：

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昆虫脂肪酰基辅酶A合成荧光素的荧光素酶活性

长链脂肪酰基辅酶A合成酶（ACSL）是萤火虫萤光素酶的同源物，但不能与萤火虫萤光素一起发光。最近，我们发现果蝇果蝇的ACSL是一种潜在的萤光素酶，它将与合成的萤光素CycLuc2一起发光。在这里，我们介绍了一组由三种昆虫ACSL组成的面板，其中包含> 20种荧光素类似物。发现不发光甲虫Agrypnus binodulus（AbLL）的ACSL是第二种潜在的萤光素酶，具有独特的底物特异性。两种刚性荧光素均通过两种ACSL发光，但苯乙烯基荧光素类似物仅是AbLL的发光底物。另一方面，来自发光甲虫Pyrophorus angustus的ACSL尽管它与甲虫萤光素酶具有较高的同源性，但所有测试的类似物都缺乏萤光素酶活性。预期ACSL的进一步研究将揭示生物发光和底物选择性所必需的特征。