Selective fluorometric detection of pyrophosphate and stringent alarmone with copper(II)–2,6-bis(2-benzimidazolyl)pyridine complex

Abstract

Pyrophosphate (PPi) is involved in lots of anabolism and bioenergetic processes in organisms and possesses important biological functions so that its detection is very significant. Here, we developed a selective fluorometric detection method for PPi with a copper(II) complex of 2,6-bis(2-benzimidazolyl)pyridine (bbimp), and then applied it to the detection of bacterial alarmone ppGpp. bbimp has the fluorescence emission at 395 nm, but the bbimp–Cu 2+ complex is hardly fluorescent because the intrinsic fluorescence of bbimp is effectively quenched by Cu 2+. With the addition of PPi, however, the fluorescence emission of bbimp turns on with a 2 nm red-shift, and has a linear relationship with PPi in the range of 3–90 μmol/L. This method has good selectivity for PPi over other anions especially those phosphate-containing anions such as ATP, UTP, CTP, GTP, GDP, and PO 4 3−.