Human thrombin info:
1670 NIH units; 3093 NIH units/mg
In light of yesterday's disappointing results, today was an information gathering day. We got in contact with David Liu, who developed the streptavidin aptamer. He and his grad student, Thomas Snyder, have not tried gel shift assays and believe that other methods such as binding the proteins to a nitrocellulose membrane or using a Biacore are more reliable.
We also tried out mfold to determine the secondary structure of our aptamers. The streptavidin aptamers leave the binding region secondary structure intact. However, the thrombin aptamers bind to themselves in the binding region, which could have well explained the lack of binding we observed. Nevertheless, such problems should have been solved by denaturation. Images to come.