FRET peptidyl sensors for the detection of metal ions

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Title: FRET peptidyl sensors for the detection of metal ions
Author: White, Brianna Rose, 1981-
Abstract: This research focuses on developing selective FRET peptidyl metal ion sensors as a portable and less costly alterative to traditional atomic spectrometric techniques . Initially , a selective sensor for Cu²⁺ was developed that consisted of glycine and aspartic acid residues and the FRET pair tryptophan (donor ) and dansyl (acceptor ) . Aspartic acid's affinity for hard acid metals and Cu²⁺'s preference for square planar coordination was used as the basis of design . Although the sensor was designed to utilize the signal enhancement capabilities of FRET , quenching of both fluorophores occurred and proved to be the most sensitive means of quantifying Cu²⁺ binding . Nonetheless , the sensor provided a selective and sensitive response to Cu²⁺ at pH 7 .0 . Another FRET peptide metal ion sensor was designed with the help of a biological starting point , the mercury binding protein MerP . A sensitive FRET enhancement or "turn on" response was observed for Hg²⁺ , as well as Zn²⁺ , Cd²⁺ and Ag²⁺ in pH 7 .0 solution . While a selective response for only Hg²⁺ was the ultimate goal of this study , this sensor is still an improvement over current systems which utilize a quenching mechanism for Hg²⁺ detection . While the previous studies investigated these sensors in aqueous solutions , the end goal was to devise a sensor based on an immobilized peptide chelator with FRET capabilities . To this end , immobilized , fluorophore labeled peptide studies were then conducted on Tentagel resin using a visible region FRET pair . A flow injection fluorescence analysis system using the immobilized fluorophore labeled peptide as the ion exchange material was also designed , allowing for the efficient analysis of fluorescence solutions . In addition to the work conducted with FRET sensors , studies were also conducted using magnetic [gamma] -Fe₂O₃ nanoparticles with PLCys immobilized onto the surface . The [gamma] -Fe₂O₃ nanoparticles are ideal supports since they can be magnetically collected and have a very large surface area to mass ratio . Finally , a method was developed to quantitatively screen metals bound to single Tentagel beads with immobilized peptides using ETV -ICP -MS . This method is an improvement over existing methods because it is nondestructive and simultaneously provides the absolute content of all metals bound .
URI: http : / /hdl .handle .net /2152 /3346
Date: 2008-08-28


FRET peptidyl sensors for the detection of metal ions. Doctoral dissertation, The University of Texas at Austin. Available electronically from http : / /hdl .handle .net /2152 /3346 .

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