Crystal Structure of Urate Oxidase from Bacillus Subtilis 168

Nayab, Anam; Moududee, Sayed Ala; Shi, Yi; Jiang, Yong-Liang; Gong, Qingguo

doi:10.1134/s1063774519070149

Cited by 2 publications

(2 citation statements)

References 36 publications

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“…π–π stacking has been demonstrated for urate–theobromine binding . Moreover, urate that crystallized with the urate oxidase enzyme in Bacillus subtilis revealed both polar and π–π stacking interactions as contributors to binding . Fluorescence-based chemosensors for urate have been reported.…”

Section: Resultsmentioning

confidence: 99%

“… 31 Moreover, urate that crystallized with the urate oxidase enzyme in Bacillus subtilis revealed both polar and π–π stacking interactions as contributors to binding. 32 Fluorescence-based chemosensors for urate have been reported. For example, Sahoo et al synthesized a naphthyridine-based fluorescent probe that demonstrated 1:1 binding stoichiometry with urate.…”

Section: Resultsmentioning

confidence: 99%

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A Copper(II) Macrocycle Complex for Sensing Biologically Relevant Organic Anions in a Competitive Fluorescence Assay: Oxalate Sensor or Urate Sensor?

et al. 2020

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Fluorescence sensing of oxalate has garnered some attention in the past two decades as a result of this anion’s prominence and impact on society. Previous work on oxalate sensors and other divalent anion sensors has led to the conclusion that the sensors are selective for the anion under investigation. However, sensor selectivity is often determined by testing against a relatively small array of “guest” molecules or analytes and studies often exclude potentially interfering compounds. For example, studies on oxalate sensors have excluded compounds such as citrate and urate, which are anions in the biological matrices where oxalate is measured ( e.g ., urine, blood, and bacterial lysate). In the present study, we reassessed the selectivity of a dinuclear copper(II) macrocycle (Cu 2 L) in an eosin Y displacement assay using biologically relevant anions. Although previously reported as selective for oxalate, we found greater indicator displacement (fluorescence response) for urate and oxaloacetate and a significant response to citrate. These anions are larger than oxalate and do not appear to fit into the putative binding pocket of Cu 2 L. Consistent with previous reports, Cu 2 L did not release eosin Y in the presence of several other dicarboxylates, including adipate, glutarate, malate (except at 10 mM), fumarate, succinate, or malonate (except at 10 mM), and the monocarboxylate acetate. This was demonstrated by the failure of the anions to reverse eosin Y quenching by Cu 2 L. We also assessed, for the first time, other monocarboxylates, including butyrate, pyruvate, lactate, propionate, and formate. None of these anions were able to displace eosin Y, indicating no interaction with Cu 2 L that interfered with the eosin Y binding site. Single-crystal X-ray crystallography revealed that nonselective binding of the anions is likely partly caused by readily accessible copper(II) ions on the external surface of Cu 2 L. In addition, π–π stacking of urate with the aromatic groups of Cu 2 L cannot be ruled out as a contributor to binding. We conclude that Cu 2 L is not suitable for oxalate sensing in a biological matrix unless interfering compounds are selectively removed or masked.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%