ABSTRACT
It has recently emerged that glutathione transferase enzymes (GSTs) and other
structurally related molecules can be translocated from the external medium into
many different cell types. In this study we aim to explore in detail, the
structural features that govern cell translocation and by dissecting the human
GST enzyme GSTM2-2 we quantatively demonstrate that the α-helical C-terminal
domain (GST-C) is responsible for this property. Attempts to further examine the
constituent helices within GST-C resulted in a reduction in cell translocation
efficiency, indicating that the intrinsic GST-C domain structure is necessary
for maximal cell translocation capacity. In particular, it was noted that the
α-6 helix of GST-C plays a stabilising role in the fold of this domain. By
destabilising the conformation of GST-C, an increase in cell translocation
efficiency of up to ∼2-fold was observed. The structural stability profiles
of these protein constructs have been investigated by circular dichroism and
differential scanning fluorimetry measurements and found to impact upon their
cell translocation efficiency. These experiments suggest that the globular,
helical domain in the ‘GST-fold’ structural motif plays a role in
influencing cellular uptake, and that changes that affect the conformational
stability of GST-C can significantly influence cell translocation
efficiency.
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Publisher: Public Library of Science
Date Published: 24-March-2011
Author(s): Morris M., Liu D., Weaver L., Board P., Casarotto M.
Link: https://doi.org/10.1371/journal.pone.0017864