蛋白质中二级结构检测方案(圆二色光谱仪)

Application NoteCDD SSpectroscopy Use of a microsampling disc for One-Drop CDspectra measurement2/3Application Note Use of a microsampling disc for One-Drop CD spectra measurement Along with NMR and X-ray crystallography， CD spectroscopyis an indispensable measurement method for proteinstructure analysis. Since small volumes and/or lowconcentrations are a typical requirement for CD samplemeasurements， JASCO has developed a novel samplingtechnique to meet these sample requirements. The technique uses a One-Drop microsampling disc (MSD)，which is shown in Figure 1.CD measurements using theOne-Drop MSD have the following advantages： 1. Small volume requirements： 10 pL (1 mm path length)，2uL (0.2 mm path length) 2. Easy handling of MSD： hydrophobic treatment of lenskeeps samples centered in disc 3. Variable path length： spacers available for 1 or 0.2 mmpath length 4. MSD windows provide artifact-free measurements 5. JASCO CD spectrometers use a parallel light beam sothere is no need for alignment 6. Highly reproducible baseline This application note will demonstrate the ease andefficiency of the One-Drop microsampling disc by measuringthe CD spectra of four proteins. Keywords One-drop measurement， microsampling disc， circulardichroism， secondary structure， J-1500 JASCO J-1500 CD spectrometer View product information at www.jascoinc.com Figure 1. Microsampling disc components(demountable cell， 2 windows and a spacer) Experimental Measurement conditions J-1500 CD spectrometer， MSD， conventional cell Spectral bandwidth 1nm Accumulation 4 times (MSD)， 1 time (conventional cell) Data acquisition interval 0.1 nm Measurement time 2.8 min (MSD)， 42 sec (conventional cell) Scan speed 100 nm/min Response time 2 sec Path length 1mm Sample concentration 0.1 mg/mL To use the microsampling disc shown in Figure 1， the sample is dropped onto the central part of the MSD. The disc is thenassembled and clamped. The MSD is then placed in a vertical position in the sample holder. MSD sample chamber 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. Themicrosampling disc (green line) provided near identical spectra compared to the cylindrical cell (blue line) used. The dataalso 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 usinga 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 reliableand quick results for small-volume and low-concentration samples. JASCO INC.Mary's Court， Easton， MD USATel： ( Fax： (pplication Library： http：//www.jascoinc.com/applications 应用说明表明，一滴式微取样盘对于小体积、低浓度样品是一种简便、快速、可靠的检测方法。