Because every protein is unique, no single tag or cleavage method will answer every need. For proteins that express well,
the simplest affinity tags may be sufficient (e.g., His6, myc). For harder to express proteins, fusion partners that enhance
folding and solubility are preferable (e.g., MBP, SUMO). Tag removal then adds another layer of complexity. When considering
which tag to use, key questions should be asked. For example, can your application tolerate retention of the tag, one or more
amino acids remaining at the cleavage site, or must tag removal leave no trace? Such questions are usually answered experimentally,
but with the availability of solubility-enhancing tags paired with highly specific proteases that cleanly remove the tag,
these questions may be moot.
Dattananda Chelur is a senior scientists, Onur Unal is a business development associate, Marc Scholtyssek is a sales manager, and James Strickler is vice president of research, all at LifeSensors, Inc., Malvern, PA, 610.644.6973, ext. 324, email@example.com
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