Fluorescent CD4 probe for potential HIV-1 gp120 protein detection

Abstract

A fluorescently modified CD4 domain 1 (mD1) protein has been designed and elaborated in an in vitro expression system. This fluorescent probe contains a Förster resonance energy transfer (FRET) pair, which uses a tryptophan residue as the fluorescence donor and an acridon-2-ylalanine (Acd) as the acceptor. When excited at 260nm, energy was transferred from tryptophan to the Acd residue of mD1, and emitted fluorescence at 420nm. This fluoresence was quenched after Evans blue (EB) inhibitor or HIV-1 gp120 protein binding, presumably as a consequence of changes in the distance and dipole orientation between the donor and acceptor; the emission intensity at 420nm decreased in a concentration-dependent fashion. This fluorescent CD4 probe could be developed into a novel tool for HIV-1 gp120 protein detection. It also could be used to screen small molecules that inhibit the gp120-CD4 interaction.

Cyanotryptophans as Novel Fluorescent Probes for Studying Protein Conformational Changes and DNA–Protein Interaction

“…A few studies have incorporated donor and acceptor amino acids into a single protein, through decoding a four-base CGGG and a nonsense UAG codon in the presence of an aminoacyl-tRNA CCCG and an aminoacyl-tRNA CUA , respectively. − Studies of this type have allowed the measurement of protein backbone cleavage and relatively large changes in protein structure. , In previous studies, we have incorporated a series of azatryptophans into E. coli dihydrofolate reductase as fluorescence donors and acridon-2-ylalanine (Acd) , as an acceptor, to study DHFR conformational changes . Here, we describe the preparation of modified DHFR containing 6-CNTrp ( A ) as a fluorescence donor and l -(7-hydroxycoumarin-4-yl)­ethylglycine (HCO, D ) as an acceptor, to permit the study of DHFR conformational changes (Figure ).…”

A sensitive fluorescence method for detection of E. Coli using rhodamine 6G dyeing

“…Although these methods possess high sensitivity and good specificity, their use of complex procedures, high cost and the high requirement for technical staff are prominent concerns. The fluorescence spectra method has been widely applied in life sciences , chemistry , and environmental science , etc., due to its simplicity, sensitivity, speed, selectivity, the requirement for less sample and its wide linear range. Rh6G is an important rhodamine dye, with good stability and a high fluorescence quantum efficiency, and has been widely applied in resonance Rayleigh scattering (RRS) , SERS , photometry , and fluorescence , etc.…”