Protein intrinsic Fluorescence for Crystal Detection or distinguishing Protein Crystals from Salt Crystals
Example 1: Protein crystals among ammonium sulfate crystals
Ammonium sulfate crystals illuminated with white light (left) and UV-light (right). The crystal structure of ammonium sulfate is orthorhombic and therefore it shows a distinct birefringence when illuminated with polarized white light. Whereas, when those crystals are illuminated with UV-light they become invisible, they completely merged with the background.
Example 2: Pure salt crystals:
Crystals of ammonium sulfate
Example 3: Crystal screening results:
A: Protein crystals (Diameter ~0.2 mm)
B: Protein crystals (Diameter ~0.1 mm)
C: Protein crystal in oily phase (Diameter ~0.3 mm)
Application 2: RNA and Aptamer Identidication applying the Nucleic Acid specific Dye "SYBR-GOLD":
Example 1: Distinguishing RNA from Salt:
In this example, an RNA-hexamer was crystallized with sodium cacodylate as precipitant. Later, under white light illumination two crystals (A, B) became visible in the drop (left). After addition of SYBER-GOLD to the drop and illumination with UV-light, crystal "A" could be identified as a salt crystal (sodium cacodylate) and crystal "B" as crystals of the RNA-hexamer.
Example 2: Aptamer-RNA Complex Identification:
Identification of included RNA inside of an Apdamer: White light illumination showed a crystal after screening. In UV-light, the crystal showed intrinsic blue fluorescence and therefore it could be identified as proteinogenic. After addition of SYBR-GOLD to the drop and illumination again with UV-light, the crystal showed green fluorescence, indicating incorporated RNA in the crystal.
In Situ DLS Applications
Highly oligomerized sample
Partially aggregated sample