Pippeting nickel-agarose resin - - OK to use a P200 pippete tip? (Jul/19/2005 )

Hi
How many of you guys have successfully used Nickel-agarose resin to capture his-tagged proteins? I always have the idea that the P200 yellow pippete tip's bore-hole is too narrow, so that the beads or the bead-bound protein may be damaged by passing through this pippete tip. So I always use a scissors to cut off 1mm from the end of the tip to make the hole bigger. Does anyone of you do that? Or do you find no problems with your experiment when you pippete using the yellow P200 tips? Thanks.

---

In ChIP assay I have to pippete the DNA/Protein A agarose slurry. Without cutting off the end of the yellow tip, I always end up with dry beads left behind simply because the diameter of the beads is bigger than the lumen of the tips. Using a tip with the end cut off solves this problem.

---

So I guess even protein A agarose requires cutting of yellow tips- is that the experience of all you guys here who pippete resin/beads with the yellow P200 tips?

---

I have never cut my Fisher brand yellow P200 tip for any agarose slurry. However, I do believe that not at all tips are created equally. I have seen some great tips that do not maintain a lot of material after discharge, and some that do. Personally, w/agarose slurries, I always use clear tips.

---

We always cut our tips. the cleanest way is to use a razor blad (gem blade) or scalpel.

---

You can also buy special wide tips, intended for this, and for handling genomic DNA with less shearing.

---