Previous proteomics studies showed that Ta0152 possesses complex
forming ability suggesting a ~500 kDa molecular weight, which size was
in good agreement with its hexadecameric homologue of Aeropyrum
pernix (Mizohata et al., 2005). Our result might indicate that the antibody
purified Ta0152 ring was prevented from ordered aggregation which
was detected in earlier studies (R. Knispel, personal communication)
therefore this complex could not be visualized by EM (data not shown).
Our scFv-antibody based two-step chromatography separation method
allowed the isolation of intact complexes from native T. acidophilum
cell extract and on the example of two well-known complexes we
demonstrated the feasibility of scFv-based purification technique for
other high molecular weight complexes. These complexes can be subjected
to biochemical and/or EM analyses however care should be taken to
carry out the experiments with several specific scFvs to avoid enzyme inhibition.
We proved the power of this method by described experiments
however to avoid unnecessary cloning steps and to increase the bait
yield creating a His-tagged nanobody displaying phage library based
on camelid immunization would be a viable option