Application 1: Protein intrinsic Fluorescence for Crystal Detection or distinguishing Protein Crystals from Salt Crystals
Example 1: Protein crystals among ammonium sulfate crystals
Example 2: Pure salt crystals:
Example 3: Crystal screening results:
Application 2: RNA and Aptamer Identidication applying the Nucleic Acid specific Dye "SYBR-GOLD":
Example 1: Distinguishing RNA from Salt:
Example 2: Aptamer-RNA Complex Identification:
Trace Labeling Procedure
Example: Sample in green light
In Situ DLS Applications
A versatile DLS-System for Cuvettes and NMR-Tubes
Examples for DLS-Analysis of Samples prior to NMR Measurements
Workflow for Cryo-EM Sample Selection
A) Condition Screening: After purification, a sample might not be in the desired aggregation state or a biological relevant complex of molecules has not formed yet. Some buffer conditions might support complex formation apart from its natural environment but often such conditions are unknown. One strategy to obtain biological complexes is the application of various conditions (e.g. sparse matrices) systematically to a sample by adding corresponding buffers. However, a manual pipetting procedure is a tedious task and errors are likely. In order to even the workflow, automated dispensing systems (like the Oryx8) are available enabling a time, material and manpower efficient way to apply such buffer matrices. Usually, standard microbatch plates and samples sealed under inert paraffin oil are used.
B) Sample Qualification: However such an approach results in many conditions (usually 96) exceeding grid holding capacities of most grid carriers by far. Furthermore, most of the applied conditions have a negative effect on the sample, leading to a very inefficient usage of a cryo-EM when all samples would be transferred to grids and investigated by cryo-EM. A key technology to select samples for subsequent cryo-EM analysis is in situ DLS (performed with the SpectroLight 600). It allows to identify suitable buffer conditions by particle size determination, non-invasively and directly in wells of a microbatch plate. Size and dispersity determination enables identification of the few conditions that stabilizes the desired macromolecular complex. The few good conditions can be selected for subsequently investigation for cryo-EM, resulting in a significant increase of positive hits on the grids.