Fernez Matthew T, Hegde Shanthi, Hayes Justin A, Hoyt Kathryn O, Carrier Rebecca L, Woolston Benjamin M
Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States.
Department of Biology, Northeastern University, Boston, Massachusetts 02115, United States.
ACS Synth Biol. 2025 Jun 20;14(6):2198-2207. doi: 10.1021/acssynbio.5c00124. Epub 2025 May 13.
Hydrogen sulfide (HS) is a gaseous gut metabolite with disputed effects on gastrointestinal health. Monitoring HS concentration in the gut would provide insight into its role in disease but is complicated by sulfide's reactivity and volatility. Here we develop a transcriptional sulfide biosensor in . The sensor relies on enzymatic oxidation of sulfide catalyzed by a sulfide:quinone oxidoreductase (Sqr) to polysulfides, which interact with the repressor SqrR, triggering unbinding from the promoter and transcription of the reporter. Through promoter engineering and improved soluble SqrR expression, we optimized the system to provide an operational range of 50-750 μM and a dynamic range of 18 aerobically. To enable sensing in anaerobic environments, we identified an Sqr from that uses menaquinone, facilitating reoxidation through the anaerobic electron transport chain by fumarate or nitrate. Use of this homologue resulted in an anaerobic HS response up to 750 μM. This sensor could ultimately enable spatially and temporally resolved measurements of HS in the gastrointestinal tract to elucidate the role of this metabolite in disease and potentially as a noninvasive diagnostic.
硫化氢（HS）是一种气态肠道代谢产物，其对胃肠道健康的影响存在争议。监测肠道中的HS浓度将有助于深入了解其在疾病中的作用，但由于硫化物的反应性和挥发性，这一过程变得复杂。在此，我们开发了一种转录硫化物生物传感器。该传感器依赖于硫化物：醌氧化还原酶（Sqr）催化的硫化物酶促氧化为多硫化物，多硫化物与阻遏物SqrR相互作用，触发其从启动子上解离并启动报告基因的转录。通过启动子工程和改进的可溶性SqrR表达，我们优化了该系统，使其工作范围为50-750μM，需氧条件下的动态范围为18。为了能够在厌氧环境中进行传感，我们从[具体来源]中鉴定出一种使用甲萘醌的Sqr，它通过富马酸盐或硝酸盐促进通过厌氧电子传递链的再氧化。使用这种同源物导致了高达750μM的厌氧HS响应。这种传感器最终能够在胃肠道中对HS进行时空分辨测量，以阐明这种代谢产物在疾病中的作用，并有可能作为一种非侵入性诊断方法。
