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Home / Applications / CD Spectra Measurement using a One Drop Microsampling Disc

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CD Spectra Measurement using a One Drop Microsampling Disc

By Heather Haffner

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January 5, 2024

Introduction

Along with NMR and X-ray crystallography, CD spectroscopy is an indispensable measurement method for protein structure analysis. Since small volumes and/or low concentrations are a typical requirement for CD sample measurements, JASCO has developed a novel sampling technique to meet these sample requirements.

The technique uses a One-Drop microsampling disc (MSD), which is shown in Figure 1. CD measurements using the One-Drop MSD have the following advantages:

  1. Small volume requirements: 10 µL (1 mm path length), 2µL (0.2 mm path length)
  2. Easy handling of MSD: hydrophobic treatment of lens keeps samples centered in disc
  3. Variable path length: spacers available for 1 or 0.2 mm path length
  4. MSD windows provide artifact-free measurements
  5. JASCO CD spectrometers use a parallel light beam so there is no need for alignment
  6. Highly reproducible baseline
  7. This application note will demonstrate the ease and efficiency of the One-Drop microsampling disc by measuring the CD spectra of four proteins.
Figure 1. Microsampling disc components(demountable cell, 2 windows and a spacer)
Figure 1. Microsampling disc components(demountable cell, 2 windows and a spacer)

Experimental

To use the microsampling disc shown in Figure 1, the sample is dropped onto the central part of the MSD. The disc is then assembled and clamped. The MSD is then placed in a vertical position in the sample holder.

Figure 2. Diagram of procedure for using the microsampling disc

Keywords

260-CD-0011, One Drop measurement, Circular Dichroism, CD

Results

The CD spectra depicted in Figure 3 compare the results obtained using the MSD and a conventional cell. The microsampling disc (green line) provided near identical spectra compared to the cylindrical cell (blue line) used. The data also show that secondary structure between 260 and 190 nm can be measured in less than three minutes using the MSD.

Figure 3. CD spectra of (A) hemoglobin, (B) lysozyme, (C) concanavalin A, and (D) trypsin inhibitor using a microsampling disc (blue) and cylindrical cell (green).

Conclusion

This application note demonstrates that the One-Drop microsampling disc is an easy to use method for obtaining reliable and quick results for small-volume and low-concentration samples.

This document has been prepared based on information available at the time of publication and is subject to revision without notice. Although the contents are checked with the utmost care, we do not guarantee their accuracy or completeness. JASCO Corporation assumes no responsibility or liability for any loss or damage incurred as a result of the use of any information contained in this document. Copyright and other intellectual property rights in this document remain the property of JASCO Corporation. Please do not attempt to copy, modify, redistribute, or sell etc. in whole or in part without prior written permission.

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About the Author

JASCO Application Note

CD Spectra Measurement using a One Drop Microsampling Disc

Introduction

Along with NMR and X-ray crystallography, CD spectroscopy is an indispensable measurement method for protein structure analysis. Since small volumes and/or low concentrations are a typical requirement for CD sample measurements, JASCO has developed a novel sampling technique to meet these sample requirements.

The technique uses a One-Drop microsampling disc (MSD), which is shown in Figure 1. CD measurements using the One-Drop MSD have the following advantages:

  1. Small volume requirements: 10 µL (1 mm path length), 2µL (0.2 mm path length)
  2. Easy handling of MSD: hydrophobic treatment of lens keeps samples centered in disc
  3. Variable path length: spacers available for 1 or 0.2 mm path length
  4. MSD windows provide artifact-free measurements
  5. JASCO CD spectrometers use a parallel light beam so there is no need for alignment
  6. Highly reproducible baseline
  7. This application note will demonstrate the ease and efficiency of the One-Drop microsampling disc by measuring the CD spectra of four proteins.
Figure 1. Microsampling disc components(demountable cell, 2 windows and a spacer)
Figure 1. Microsampling disc components(demountable cell, 2 windows and a spacer)

Experimental

To use the microsampling disc shown in Figure 1, the sample is dropped onto the central part of the MSD. The disc is then assembled and clamped. The MSD is then placed in a vertical position in the sample holder.

Figure 2. Diagram of procedure for using the microsampling disc

Results

The CD spectra depicted in Figure 3 compare the results obtained using the MSD and a conventional cell. The microsampling disc (green line) provided near identical spectra compared to the cylindrical cell (blue line) used. The data also show that secondary structure between 260 and 190 nm can be measured in less than three minutes using the MSD.

Figure 3. CD spectra of (A) hemoglobin, (B) lysozyme, (C) concanavalin A, and (D) trypsin inhibitor using a microsampling disc (blue) and cylindrical cell (green).

Conclusion

This application note demonstrates that the One-Drop microsampling disc is an easy to use method for obtaining reliable and quick results for small-volume and low-concentration samples.

Keywords

260-CD-0011, One Drop measurement, Circular Dichroism, CD

This document has been prepared based on information available at the time of publication and is subject to revision without notice. Although the contents are checked with the utmost care, we do not guarantee their accuracy or completeness. JASCO Corporation assumes no responsibility or liability for any loss or damage incurred as a result of the use of any information contained in this document. Copyright and other intellectual property rights in this document remain the property of JASCO Corporation. Please do not attempt to copy, modify, redistribute, or sell etc. in whole or in part without prior written permission.
28600 Mary’s Court, Easton, MD 21601 USA • (800) 333-5272 • Fax: (410) 822-7526 • jascoinc.com/applications

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