Structure-guided activity restoration of the silkworm glutathione transferase Omega GSTO3-3
Chen, B.-Y., Ma, X.-X., Guo, P.-C., Tan, X., Li, W.-F., Yang, J.-P., Zhang, N.-N., Chen, Y., Xia, Q., Zhou, C.-Z.(2011) J Mol Biol 412: 204-211
- PubMed: 21816159
- DOI: https://doi.org/10.1016/j.jmb.2011.07.019
- Primary Citation of Related Structures:
3RBT - PubMed Abstract:
Glutathione transferases (GSTs) are ubiquitous detoxification enzymes that conjugate hydrophobic xenobiotics with reduced glutathione. The silkworm Bombyx mori encodes four isoforms of GST Omega (GSTO), featured with a catalytic cysteine, except that bmGSTO3-3 has an asparagine substitution of this catalytic residue. Here, we determined the 2.20-Å crystal structure of bmGSTO3-3, which shares a typical GST overall structure. However, the extended C-terminal segment that exists in all the four bmGSTOs occupies the G-site of bmGSTO3-3 and makes it unworkable, as shown by the activity assays. Upon mutation of Asn29 to Cys and truncation of the C-terminal segment, the in vitro GST activity of bmGSTO3-3 could be restored. These findings provided structural insights into the activity regulation of GSTOs.
Organizational Affiliation:
School of Life Sciences and Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.