Profiling Esterases in Mycobacterium tuberculosis Using Far-Red Fluorogenic Substrates

• Published in: ACS chemical biology 2016-07, Vol.11 (7), p.1810-1815
• Main Authors: Tallman, Katie R, Levine, Samantha R, Beatty, Kimberly E
• Format: Article
• Language: English
• Subjects: Esterases - metabolism; Fluorescent Dyes - chemistry; Mycobacterium tuberculosis - enzymology; Nuclear Magnetic Resonance, Biomolecular; Substrate Specificity
• ISSN: 1554-8929; 1554-8937
• DOI: 10.1021/acschembio.6b00233

Enzyme-activated, fluorogenic probes are powerful tools for studying bacterial pathogens, including Mycobacterium tuberculosis (Mtb). In prior work, we reported two 7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one) (DDAO)-derived acetoxymethyl ether probes for esterase and lipase detection. Here, we report four-carbon (C4) and eight-carbon (C8) acyloxymethyl ether derivatives, which are longer-chain fluorogenic substrates. These new probes demonstrate greater stability and lipase reactivity than the two-carbon (C2) acetoxymethyl ether-masked substrates. We used these new C4 and C8 probes to profile esterases and lipases from Mtb. The C8-masked probes revealed a new esterase band in gel-resolved Mtb lysates that was not present in lysates from nonpathogenic M. bovis (bacillus Calmette-Guérin), a close genetic relative. We identified this Mtb-specific enzyme as the secreted esterase Culp1 (Rv1984c). Our C4- and C8-masked probes also produced distinct Mtb banding patterns in lysates from Mtb-infected macrophages, demonstrating the potential of these probes for detecting Mtb esterases that are active during infections.