Programming A Molecular Relay for Ultrasensitive Biodetection through (129)Xe NMR.
Publication Type:Journal Article
Source:Angew Chem Int Ed Engl, Volume 55, Issue 5, p.1733-6 (2016)
Keywords:Crystallography, X-Ray, Limit of Detection, Magnetic Resonance Spectroscopy, Xenon
<p>A supramolecular strategy for detecting specific proteins in complex media by using hyperpolarized (129) Xe NMR is reported. A cucurbituril (CB)-based molecular relay was programmed for three sequential equilibrium conditions by designing a two-faced guest (TFG) that initially binds CB and blocks the CB-Xe interaction. The protein analyte recruits the TFG and frees CB for Xe binding. TFGs containing CB- and carbonic anhydrase II (CAII)-binding domains were synthesized in one or two steps. X-ray crystallography confirmed TFG binding to Zn(2+) in the deep CAII active-site cleft, which precludes simultaneous CB binding. The molecular relay was reprogrammed to detect avidin by using a different TFG. Finally, Xe binding by CB was detected in buffer and in E. coli cultures expressing CAII through ultrasensitive (129) Xe NMR spectroscopy.</p>