English
Molecular Docking-Based Interpretation of the Substrate Specificity and Cell Wall Polysaccharide Elongation Mechanisms of GT2 and GT3 in Trichoderma harzianum
Dong-Ryeol Yu1, Jun Seok Oh1, Ju Young Park1, Tae-Seok Oh1,
Youn-Jin Park2, Myoung-Jun Jang1,3*
1Department of Plant Resources, Kongju National University,
2Kongju National University Legumes Green Manure Resource Center
3Center for Smart Future Agricultural Education and Research, College of Industrial Sciences, Kongju National University
*Email: plant119@kongju.ac.kr
This study used molecular docking analysis to interpret the substrate recognition modes and structure-based functions of GT2 and GT3 in Trichoderma harzianum. For GT2, UDP-GlcNAc was used as the donor and chitobiose as the acceptor, whereas for GT3, UDP-Glc was used as the donor and maltose as the acceptor. Docking analysis showed that both proteins contained donor-anchoring residue clusters composed mainly of Lys and Arg residues around the nucleotide-sugar moiety of the donor, while the acceptors were positioned adjacent to the donor sugar along a groove or interdomain cleft. In GT2, the donor GlcNAc was located near the non-reducing end of chitobiose, and Lys-1060 and Arg-1253 were positioned to anchor UDP, supporting a chitin synthase-like function that extends the β-1,4-GlcNAc chain at the plasma membrane. In GT3, Arg-317 and Lys-323 were located around UDP, and maltose was arranged within the cleft in a manner resembling the terminal end of an α-1,4-glucan chain, supporting structural features consistent with α-glucan chain elongation. These results suggest that GT2 and GT3 may function as glycosyltransferases involved in chitin and α-glucan synthesis, respectively, and provide a structural basis for interpreting their contributions to cell wall stability and morphological maintenance in T. harzianum.
