scholarly journals Characterisation of sensor kinase by CD spectroscopy: golden rules and tips

2018 ◽  
Vol 46 (6) ◽  
pp. 1627-1642 ◽  
Author(s):  
Giuliano Siligardi ◽  
Charlotte S. Hughes ◽  
Rohanah Hussain
Keyword(s):  
Circular Dichroism ◽  
Membrane Proteins ◽  
Conformational Changes ◽  
High Throughput Screening ◽  
Local Environment ◽  
Cd Spectroscopy ◽  
Photon Flux ◽  
Minimal Amount ◽  
Sensor Kinase ◽  
Circular Dichroïsm

This is a review that describes the golden rules and tips on how to characterise the molecular interactions of membrane sensor kinase proteins with ligands using mainly circular dichroism (CD) spectroscopy. CD spectroscopy is essential for this task as any conformational change observed in the far-UV (secondary structures (α-helix, β-strands, poly-proline of type II, β-turns, irregular and folding) and near-UV regions [local environment of the aromatic side-chains of amino acid residues (Phe, Tyr and Trp) and ligands (drugs) and prosthetic groups (porphyrins, cofactors and coenzymes (FMN, FAD, NAD))] upon ligand addition to the protein can be used to determine qualitatively and quantitatively ligand-binding interactions. Advantages of using CD versus other techniques will be discussed. The difference CD spectra of the protein–ligand mixtures calculated subtracting the spectra of the ligand at various molar ratios can be used to determine the type of conformational changes induced by the ligand in terms of the estimated content of the various elements of protein secondary structure. The highly collimated microbeam and high photon flux of Diamond Light Source B23 beamline for synchrotron radiation circular dichroism (SRCD) enable the use of minimal amount of membrane proteins (7.5 µg for a 0.5 mg/ml solution) for high-throughput screening. Several examples of CD titrations of membrane proteins with a variety of ligands are described herein including the protocol tips that would guide the choice of the appropriate parameters to conduct these titrations by CD/SRCD in the best possible way.

Circular dichroism and synchrotron radiation circular dichroism spectroscopy: tools for drug discovery

2003 ◽  
Vol 31 (3) ◽  
pp. 631-633 ◽  
Author(s):  
B.A. Wallace ◽  
Robert W. Janes
Keyword(s):  
Circular Dichroism ◽  
Drug Discovery ◽  
Synchrotron Radiation ◽  
High Throughput ◽  
Conformational Changes ◽  
High Throughput Screening ◽  
Cd Spectroscopy ◽  
Drug Binding ◽  
Apoptosis Protein ◽  
Circular Dichroïsm

CD spectroscopy is an established and valuable technique for examining protein structure, dynamics and folding. Because of its ability to sensitively detect conformational changes, it has important potential for drug discovery, enabling screening for ligand and drug binding, and detection of potential candidates for new pharmaceuticals. The binding of the anti-tumour agent Taxol to the anti-apoptosis protein Bcl-2 [Rodi, Janes, Sanganee, Holton, Wallace and Makowski (1999) J. Mol. Biol. 285, 197–204] and the binding of the anti-epileptic drug lamotrigine to voltage-gated sodium channels [Cronin, O'Reilly, Duclohier and Wallace (2003) J. Biol. Chem. 278, 10675–10682] are used as examples to show changes detectable by CD involving secondary structure, and are contrasted with the binding of the agonist carbamylcholine to acetylcholine receptors [Mielke and Wallace (1988) J. Biol. Chem. 263, 8177–8182], an example where binding does not involve a secondary structural change. Synchrotron radiation CD spectroscopy offers significant enhancements with respect to conventional CD spectroscopy, which will enable its usage for high-throughput screening and as a tool in ‘chemical genomics’ or ‘reverse chemical genetics’ strategies for ligand identification. The lower wavelength data available enable more detailed, sensitive and accurate detection, the higher light intensity permits much smaller amounts of both proteins and drug candidates to be used in the screening, and future technological developments in sample handling and detection should enable automated high-throughput screening to be performed.

scholarly journals Tapping into Synchrotron and Benchtop Circular Dichroism Spectroscopy for Expanding Studies of Complex Polysaccharides and their Interactions in Anoxic Archaeological Wood

Heritage ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 121-134
Author(s):  
Mary K. Phillips-Jones ◽  
Stephen E. Harding
Keyword(s):  
Circular Dichroism ◽  
Conformational Changes ◽  
Spectral Characteristics ◽  
Visible Region ◽  
Cd Spectroscopy ◽  
Future Research ◽  
Ultraviolet Region ◽  
Synchrotron Source ◽  
Archaeological Wood ◽  
Circular Dichroïsm

Circular dichroism (CD) (and synchrotron circular dichroism (SCD)) spectroscopy is a rapid, highly sensitive technique used to investigate structural conformational changes in biomolecules in response to interactions with ligands in solution and in film. It is a chiroptical method and at least one of the interacting molecules must possess optical activity (or chirality). In this review, we compare the capabilities of CD and SCD in the characterisation of celluloses and lignin polymers in archaeological wood. Cellulose produces a range of spectral characteristics dependent on environment and form; many of the reported transitions occur in the vacuum-ultraviolet region (< 180 nm) most conveniently delivered using a synchrotron source. The use of induced CD in which achiral dyes are bound to celluloses to give shifted spectra in the visible region is also discussed, together with its employment to identify the handedness of the chiral twists in nanocrystalline cellulose. Lignin is one target for the design of future consolidants that interact with archaeological wood to preserve it. It is reportedly achiral, but here we review several studies in which CD spectroscopy has successfully revealed lignin interactions with chiral enzymes, highlighting the potential usefulness of the technique in future research to identify new generation consolidants.

scholarly journals Synthesis of a sucrose dimer with enone tether; a study on its functionalization

2014 ◽  
Vol 10 ◽  
pp. 1246-1254 ◽  
Author(s):  
Zbigniew Pakulski ◽  
Norbert Gajda ◽  
Magdalena Jawiczuk ◽  
Jadwiga Frelek ◽  
Piotr Cmoch ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Double Bond ◽  
Carbonyl Group ◽  
Osmium Tetroxide ◽  
Cd Spectroscopy ◽  
Allylic Alcohol ◽  
Circular Dichroïsm

The reaction of appropriately functionalized sucrose phosphonate with sucrose aldehyde afforded a dimer composed of two sucrose units connected via their C6-positions (‘the glucose ends’). The carbonyl group in this product (enone) was stereoselectively reduced with zinc borohydride and the double bond (after protection of the allylic alcohol formed after reduction) was oxidized with osmium tetroxide to a diol. Absolute configurations of the allylic alcohol as well as the diol were determined by circular dichroism (CD) spectroscopy using the in situ dimolybdenum methodology.

scholarly journals Conformational changes in the H3 . H4 histone complex. Serological and circular dichroism studies.

1980 ◽  
Vol 255 (15) ◽  
pp. 7059-7062
Author(s):  
L. Feldman ◽  
N.V. Beaudette ◽  
B.D. Stollar ◽  
G.D. Fasman
Keyword(s):  
Circular Dichroism ◽  
Conformational Changes ◽  
Circular Dichroïsm

scholarly journals Circular dichroism spectroscopy of membrane proteins

2016 ◽  
Vol 45 (18) ◽  
pp. 4859-4872 ◽  
Author(s):  
A. J. Miles ◽  
B. A. Wallace
Keyword(s):  
Circular Dichroism ◽  
Membrane Proteins ◽  
Circular Dichroism Spectroscopy ◽  
Circular Dichroism Spectra ◽  
Helical Bundle ◽  
Beta Barrel ◽  
Circular Dichroïsm

Circular dichroism spectra of helical bundle (red), beta barrel (blue), and mixed helical/sheet/unordered (green) membrane proteins.

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.

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