How to suppress the spontaneous oscillatory in-vitro chiral conversion of α-substituted propionic acids? A thin-layer chromatographic, polarimetric, and circular dichroism study of complexation of the Cu(II) cation withl-lactic acid

2009 ◽  
Vol 21 (1) ◽  
pp. 39-55 ◽  
Author(s):  
M. Sajewicz ◽  
E. John ◽  
D. Kronenbach ◽  
M. Gontarska ◽  
M. Wróbel ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Circular Dichroism ◽  
Thin Layer ◽  
Circular Dichroïsm

scholarly journals Electronic Circular Dichroism of the Cas9 Protein and gRNA:Cas9 Ribonucleoprotein Complex

2021 ◽  
Vol 22 (6) ◽  
pp. 2937
Author(s):  
Monika Halat ◽  
Magdalena Klimek-Chodacka ◽  
Jagoda Orleanska ◽  
Malgorzata Baranska ◽  
Rafal Baranski
Keyword(s):  
Circular Dichroism ◽  
Conformational Changes ◽  
Structural Changes ◽  
Electronic Circular Dichroism ◽  
Guide Rna ◽  
Cas9 Protein ◽  
Rnp Complex ◽  
Characteristic Features ◽  
Circular Dichroïsm

The Streptococcus pyogenes Cas9 protein (SpCas9), a component of CRISPR-based immune system in microbes, has become commonly utilized for genome editing. This nuclease forms a ribonucleoprotein (RNP) complex with guide RNA (gRNA) which induces Cas9 structural changes and triggers its cleavage activity. Here, electronic circular dichroism (ECD) spectroscopy was used to confirm the RNP formation and to determine its individual components. The ECD spectra had characteristic features differentiating Cas9 and gRNA, the former showed a negative/positive profile with maxima located at 221, 209 and 196 nm, while the latter revealed positive/negative/positive/negative pattern with bands observed at 266, 242, 222 and 209 nm, respectively. For the first time, the experimental ECD spectrum of the gRNA:Cas9 RNP complex is presented. It exhibits a bisignate positive/negative ECD couplet with maxima at 273 and 235 nm, and it differs significantly from individual spectrum of each RNP components. Additionally, the Cas9 protein and RNP complex retained biological activity after ECD measurements and they were able to bind and cleave DNA in vitro. Hence, we conclude that ECD spectroscopy can be considered as a quick and non-destructive method of monitoring conformational changes of the Cas9 protein as a result of Cas9 and gRNA interaction, and identification of the gRNA:Cas9 RNP complex.

The important role of non-covalent interactions for the vibrational circular dichroism of lactic acid in aqueous solution

2021 ◽  
Author(s):  
Sascha Jähnigen ◽  
Daniel Sebastiani ◽  
Rodolphe Vuilleumier
Keyword(s):  
Lactic Acid ◽  
Circular Dichroism ◽  
Computational Study ◽  
Bulk Water ◽  
Vibrational Circular Dichroism ◽  
Ab Initio Molecular Dynamics ◽  
Non Covalent Interactions ◽  
Circular Dichroïsm ◽  
Covalent Interactions

We present a computational study of vibrational circular dichroism (VCD) in solutions of (S)-lactic acid, relying on ab initio molecular dynamics (AIMD) and full solvation with bulk water. We discuss...

Aggregation of lactic acid in cold rare-gas matrices and the link to solution: a matrix isolation-vibrational circular dichroism study

2019 ◽  
Vol 21 (7) ◽  
pp. 3574-3584 ◽  
Author(s):  
Angelo Shehan Perera ◽  
Joseph Cheramy ◽  
Mohammad Reza Poopari ◽  
Yunjie Xu
Keyword(s):  
Lactic Acid ◽  
Circular Dichroism ◽  
Matrix Isolation ◽  
Vibrational Circular Dichroism ◽  
Rare Gas ◽  
Spectral Features ◽  
Circular Dichroïsm ◽  
Self Aggregation ◽  
Insight Into

Crucial insight into lactic acid self-aggregation in solution is obtained by following its unique VCD spectral features in cold matrices.

The near infra red (NIR) chiroptical properties of nickel dithiolene complexes

2015 ◽  
Vol 39 (1) ◽  
pp. 122-129 ◽  
Author(s):  
Yann Le Gal ◽  
Antoine Vacher ◽  
Vincent Dorcet ◽  
Marc Fourmigué ◽  
Jeanne Crassous ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Thin Layer ◽  
Chiroptical Properties ◽  
Infra Red ◽  
Redox Switching ◽  
Circular Dichroïsm

Circular dichroism (CD) thin layer spectro-electrochemical experiments reveal a redox switching of CD-active bands in the NIR region.

Lateral, Chiral Tin(IV) Porphyrin Assemblies

1998 ◽  
Vol 02 (03) ◽  
pp. 273-284 ◽  
Author(s):  
BIANCA ROSENGARTEN ◽  
CHRISTOPH BÖTTCHER ◽  
ANDREA SCHULZ ◽  
J.-H. FUHRHOP ◽  
ULRICH SIGGEL
Keyword(s):  
Hydrogen Bonding ◽  
Lactic Acid ◽  
Circular Dichroism ◽  
Hydrochloric Acid ◽  
Protoporphyrin Ix ◽  
Mirror Image ◽  
Chloride Ions ◽  
Hydrogen Atoms ◽  
Circular Dichroism Spectra ◽  
Circular Dichroïsm

The μ-Oxo stacks of tin(IV) porphyrins rearrange to staircase-type and lateral aggregates upon replacement of the oxygen ligands by chloride ions. The lateral aggregation of tin(IV) 2,18-dipropionate porphyrins in hydrochloric acid at pH 0–0.5 is favoured by 8,13-ethyl groups instead of the natural 8,13-vinyl groups of protoporphyrin IX and is impeded by hydrogen atoms at these positions. Replacement of axial chloride counterions to the tin(IV) central ions by cyanate counterions at pH 4.5 leads to similar aggregates if the cyanate ions are connected by hydrogen bonding to acetic or lactic acid. In this case, aggregation is not necessarily impeded by hydrogen atoms at positions 8 and 13. D- and L-lactic acid enforce chiral assemblies of the tin(IV) deuteroporphyrin 1a with mirror image CD (circular dichroism) spectra (θ ≈ 8 × 105 deg cm 2 dmol −1), whereas the gluconoyl hydrazide-substituted tin(IV) deuteroporphyrin 1d does not form aggregates at all.

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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