Tandem affinity purification vectors for use in gram positive bacteria.

Tandem affinity purification has become a valuable tool for the isolation of protein complexes. Here we describe the construction and use of a series of plasmid vectors for Gram positive bacteria. The vectors utilize the SPA tag as well as variants containing a 3C rather than the TEV protease site as 3C protease has been shown to work efficiently at the low temperatures (4 degrees C) used to isolate protein complexes. In addition, a further vector incorporates a GST moiety in place of the 3xFLAG of the SPA tag which provides an additional tagging option for situations where SPA binding may be inefficient. The vectors are all compatible with previously constructed fluorescent protein fusion vectors enabling construction of a suite of affinity and fluorescently tagged genes using a single PCR product.