scholarly journals Whole-cell circular dichroism difference spectroscopy reveals an in vivo-specific deca-heme conformation in bacterial surface cytochromes

2018 ◽  
Vol 54 (99) ◽  
pp. 13933-13936 ◽  
Author(s):  
Yoshihide Tokunou ◽  
Punthira Chinotaikul ◽  
Shingo Hattori ◽  
Thomas A. Clarke ◽  
Liang Shi ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Analytical Framework ◽  
Difference Spectroscopy ◽  
Whole Cell ◽  
Bacterial Surface ◽  
System P ◽  
Circular Dichroïsm

Our novel analytical framework to identify the inter-heme interaction in deca-heme cytochrome protein MtrC in whole cell revealed that the heme alignment in reduced MtrC is distinct from that in purified system.

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.

The thermal denaturation of bovine cardiac G-actin

1977 ◽  
Vol 55 (4) ◽  
pp. 325-331 ◽  
Author(s):  
C. C. Contaxis ◽  
C. C. Bigelow ◽  
C. G. Zarkadas
Keyword(s):  
Circular Dichroism ◽  
Conformational Change ◽  
Thermodynamic Analysis ◽  
Thermal Denaturation ◽  
State Transition ◽  
Thermal Unfolding ◽  
Difference Spectroscopy ◽  
Maximum Stability ◽  
Ph Range ◽  
Circular Dichroïsm

The thermal denaturation of bovine cardiac G-actin has been studied by ultraviolet difference spectroscopy and circular dichroism between pH 7.5 and 10.5. As with proteins previously studied, thermal unfolding is incomplete compared with unfolding by urea or GuHCl. However, the same conformational change is observed over the pH range studied, and the available evidence indicates it is a two-state transition. Thermodynamic analysis of the data shows that ΔH0 and ΔS0 are strongly dependent on the temperature, that ΔCp is 1300 cal deg−1 mol−1, and that G-actin has a temperature of maximum stability near −5 °C.

A Circular Dichroism and Photoacoustic Dual-Mode Probe for Detection In Vitro and Imaging In Vivo of Hydroxyl Radicals

2022 ◽  
Author(s):  
Shulong Wang ◽  
Liangliang Zhang ◽  
Yanni Luo ◽  
Yulong Bai ◽  
Yong Huang ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Hydroxyl Radicals ◽  
Dual Mode ◽  
Circular Dichroïsm
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