Related Experiment Video
Updated: Aug 14, 2026

Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
Published on: November 1, 2012
Overproduction, purification and crystallization of TaqI restriction endonuclease
1Department of Microbiology, Hearst Microbiology Research Center, Cornell University Medical College, New York, NY 10021.
Abstract:
Under phoA promoter control, TaqI endonuclease was overproduced to 5% of Escherichia coli cellular proteins. This was achieved by fusing the endonuclease gene to the first four codons of the alkaline phosphatase signal sequence. For maximal overproduction (30% of cellular proteins), a putative 14-bp hairpin within the endonuclease coding sequence was replaced with degenerate codons. In addition, TaqI methylase was required to protect host DNA. The endonuclease was purified in sufficient amounts for crystallization.
More Related Videos
Related Concept Videos
Restriction Enzymes
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
Downstream Processing

