In structural biology projects, one early hurdle is often the protein
of interest being insoluble. This problem is common when eukaryotic
recombinant proteins are overproduced in bacterial hosts. In
many cases, the insolubility problem cannot be overcome by modulating
the growth and induction condition of the culture. It has been
reported that some proteins, despite depositing as inclusion bodies,
retain their native structures and functions. One promising approach
is therefore to recover these protein samples from the solid phase
employing a mild detergent. However, protein samples extracted
from inclusion bodies usually contain nucleic-acid contaminants [ 1 ].
Here we describe an easy procedure for monitoring these contaminations
and we discuss how these can be removed or avoided.