An On/Off Circular Dichroism Signal Reveals a pH Dependent Competition between a Cyclodextrin and a Polyelectrolyte for an Atropisomeric Aromatic Guest

1997 ◽  
Vol 119 (50) ◽  
pp. 12404-12405 ◽  
Author(s):  
Sung Yun Yang ◽  
Mark M. Green ◽  
Gerald Schultz ◽  
Salil K. Jha ◽  
Axel H. E. Müller
Keyword(s):  
Circular Dichroism ◽  
Circular Dichroism Signal ◽  
Aromatic Guest ◽  
Ph Dependent ◽  
Circular Dichroïsm

In situ generated pyroglutamate bridged polyoxotitaniums with strong circular dichroism signal

2019 ◽  
Vol 30 (5) ◽  
pp. 1005-1008 ◽  
Author(s):  
Guo-Liang Dong ◽  
Wei-Hui Fang ◽  
Lei Zhang ◽  
Jian Zhang
Keyword(s):  
Circular Dichroism ◽  
Circular Dichroism Signal ◽  
Circular Dichroïsm

On the Calculation of an X-Ray Natural Circular Dichroism Signal

2018 ◽  
Vol 73 (3) ◽  
pp. 314-324
Author(s):  
A. P. Oreshko ◽  
E. N. Ovchinnikova ◽  
K. A. Kozlovskaya ◽  
V. E. Dmitrienko
Keyword(s):  
Circular Dichroism ◽  
Circular Dichroism Signal ◽  
X Ray ◽  
Circular Dichroïsm

scholarly journals Circular Dichroism of Chromopeptides from Phycocyanin

1983 ◽  
Vol 38 (11-12) ◽  
pp. 951-959 ◽  
Author(s):  
C. Schamagl ◽  
E. Köst-Reyes ◽  
S. Schneider ◽  
H.-P. Köst ◽  
H. Scheer
Keyword(s):  
Circular Dichroism ◽  
Aqueous Solutions ◽  
Optical Activity ◽  
Ph Dependence ◽  
Acidic Ph ◽  
Sign Reversal ◽  
Aqueous Buffer ◽  
Ph Dependent ◽  
Circular Dichroïsm

The circular dichroism of bilipeptides from Spirulina geitleri phycocyanin is strongly solvent and pH dependent. Maximum optical activity has been observed in aqueous solutions containing urea (8 ᴍ). In aqueous buffer, a sign reversal occurred upon the change from neutral to acidic pH; in methanolic solutions shows the optical activity a strong pH dependence both with respect to sign and magnitude. These findings have been rationalized by the presence of chrom ophorepeptide interactions, which are minimized in the presence of urea. M olecular orbital calculations indicate that the observed sign reversal is not necessarily due to a reversal of the chirality of the entire chromophore, but may also result from more localized conform ational changes

scholarly journals Peptides of pHLIP family for targeted intracellular and extracellular delivery of cargo molecules to tumors

2018 ◽  
Vol 115 (12) ◽  
pp. E2811-E2818 ◽  
Author(s):  
Linden C. Wyatt ◽  
Anna Moshnikova ◽  
Troy Crawford ◽  
Donald M. Engelman ◽  
Oleg A. Andreev ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Targeted Delivery ◽  
Tumor Imaging ◽  
Intracellular Delivery ◽  
Membrane Lipid ◽  
Wide Range ◽  
Ph Dependent ◽  
Circular Dichroïsm

The pH (low) insertion peptides (pHLIPs) target acidity at the surfaces of cancer cells and show utility in a wide range of applications, including tumor imaging and intracellular delivery of therapeutic agents. Here we report pHLIP constructs that significantly improve the targeted delivery of agents into tumor cells. The investigated constructs include pHLIP bundles (conjugates consisting of two or four pHLIP peptides linked by polyethylene glycol) and Var3 pHLIPs containing either the nonstandard amino acid, γ-carboxyglutamic acid, or a glycine−leucine−leucine motif. The performance of the constructs in vitro and in vivo was compared with previous pHLIP variants. A wide range of experiments was performed on nine constructs including (i) biophysical measurements using steady-state and kinetic fluorescence, circular dichroism, and oriented circular dichroism to study the pH-dependent insertion of pHLIP variants across the membrane lipid bilayer; (ii) cell viability assays to gauge the pH-dependent potency of peptide-toxin constructs by assessing the intracellular delivery of the polar, cell-impermeable cargo molecule amanitin at physiological and low pH (pH 7.4 and 6.0, respectively); and (iii) tumor targeting and biodistribution measurements using fluorophore-peptide conjugates in a breast cancer mouse model. The main principles of the design of pHLIP variants for a range of medical applications are discussed.

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