Oryx 6 for Protein Crystallization with
Oryx 6 Robot
Oryx 6 is driven by a PC, which is connected to a stepper motor drive box (MCC). This is connected to 6 motorized syringes (1 large and 5 small) mounted at the back of the chassis, and to the XYZV Plate Loader, which has a moving table and two arms.
· Small volumes are dispensed by the left-hand arm, using the five small (100 µl) motorized syringes.
· Small volumes are dispensed from a two-bore or five-bore microtip.
· Stock solutions do not come into contact with the motorized syringes, which are filled with degassed pure water - this avoids the need for flushing out the syringes when the stock solutions are changed.
· The manual syringes on the front panel are used to refill the motorized syringes, to remove air bubbles, and to load stock solutions.
· Large volumes, including oil for microbatch experiments and reservoir solutions for vapor diffusion experiments, are dispensed by the right-hand arm using the large (10 ml) motorized syringe. A 1 ml disposable tip is used for this.
2. What it does
a. Microbatch screening
The most popular use of Oryx 6 is for screening (finding new crystallization conditions) using the microbatch crystallization method. Here droplets are dispensed into plastic plates and covered with oil to prevent evaporation. (We normally use HLA or Vapor Batch plates. These have wells that hold about 10 μl - we generally dispense 0.2 to 2 µl into the bottom of each well.) In order to dispense these very small droplets accurately, a special proprietary microtip is used.
Oryx has an extra liquid handling channel that can be used to cover microbatch droplets with oil immediately after dispensing. This prevents the microtip from coming into contact with the oil, which would significantly reduce accuracy. (This is the reason that Oryx is more accurate than IMPAX for dispensing microbatch experiments.)
Typically 96 premixed solutions can be combined with protein for screening. These solutions are placed on the right-hand side of the Plate Loader. A two-channel microtip is used to mix the solutions with protein. One channel is loaded with the correct amount of protein at the start of the experiment. The other channel is used to pick up 0.1 to 1 µl of the first screening solution and transfer it to the first well of the VB plate. It is dispensed and mixed with 0.1 to 1 µl of protein from the other channel. Oil is immediately dispensed by the second arm to cover and protect the drop. The microtip is then rinsed. This is repeated for all 96 solutions. It takes about 5 minutes for the user to set up a screening experiment, and 50 minutes to dispense a screen with 96 solutions.
The regular software includes routines for Hampton Research Crystal Screens etc.
Click here for details of the screening liquid handling routines for Oryx.
b. Microbatch optimization
A sophisticated “spreadsheet” environment is provided for designing and carrying out optimization experiments. The stock solutions are shown on the left. Each cell represents one well. The user can input concentrations simply by double-clicking on a well.
By defining the wells at opposite corners of a block, and selecting “interpolate”, the user can rapidly define 2D grids. A similar routine automatically generates a four-dimensional multivariate experimental design. Here the conditions are based on the conditions in a single well – the user chooses the total amount of variation that he would like for each variable as a percentage. See our research report “Practical Experimental Design Techniques” for more details.
The branches of the 5-channel microtip act as reservoirs for protein, precipitant, pH buffer solutions and additives. These are loaded using the lower row of valves and the disposable syringes. Solutions are dispensed using the motorized gas-tight syringes, which contain water.
Exactly the right amount of protein is loaded by sucking it into one bore of
the microtip. It is kept separate from the water
already in the bore by a small air bubble. Solutions are dispensed from all
bores simultaneously. 96 wells can be dispensed in around 15 minutes. As with screening, oil is dispensed by Oryx onto each droplet immediately
after it is dispensed.
c. Sitting Drop Crystallization
Oryx can rapidly dispense the droplets into trays such as
Crystal Clear, Cryschem, Greiner or
Filling reservoirs for Sitting Drop screens
Oryx has a motorized 10 ml syringe which is connected to a disposable tip. This can be used to transfer solutions from a mother plate to the reservoirs of a sitting drop plate.
Oryx 6 costs £36,000
10% discounts are offered to universities and 5% discounts to government institutes.
Click below for:
©2004 Douglas Instruments Ltd