Despite numerous reports on molecule/metal ions sensing using excited-state intramolecular proton transfer (ESIPT) as a signal transducers, their pragmatic applications in biomedia are obscure. Main obstacles lie in two folds. Firstly, water provides strong and highest density of hydrogen bonding sites that perturb the ESIPT systems. Thus ESIPT is most likely, or in part, prohibited in water. Furthermore, water molecules in general act as a strong ligand that are competitive with the guest molecules for the coordination binding. An alternative solution of this obstacle is to fully exploit water molecules for the assistance rather than the prohibition of ESIPT. In this talk I will focus on the current progress of excited state water catalyzed proton transfer reaction in a series of 7-azaindole derivatives. From the fundamental point of view, we establish the structure/proton transfer relationship in water. On this basis, a tryptophan analogue 2,7-diazatryptopnan was strategically designed. The water sensitive multiple emission of 2,7-diazatryptopnan serves as a novel sensor to probe the proximal water environment of tryptophan in a number of proteins of interest. An exquisite case in point is demonstrated by examining the structurally pending human thromboxane A2 synthase (TXAS) by site-specifically replacing tryptophan residues with 2,7-diazatryptopnan and the results successfully differentiate the water environment among the five tryptophans in TXAS, demonstrating for the first time the feasibility of sensing bio-waters in proteins. The characteristic multiple emission manifested by water catalyzed proton transfer tautomerism may lead to the feasibility of probing how water molecules affect the folding, structures and activities of proteins. Some of our current focus will be presented as well in this talk. Pi-Tai Chou, et al., J. Am. Chem. Soc. 2011 , 133, 18870-18879Pi-Tai Chou, et al., Biochemistry 2013 , 52, 1113-1121Pi-Tai Chou, et al., Nature Commun. 2013 , 4, 2611

Excited-state water catalyzed proton transfer reaction: Fundamental and biomedical applications

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.