Crystal structures of Magnaporthe oryzae trehalose-6-phosphate synthase (MoTps1) suggest a model for catalytic process of Tps1

Abstract

Trehalose-6-phosphate (T6P) synthase (Tps1) catalyzes the formation of T6P from UDP-glucose (UDPG) (or GDPG, etc.) and glucose-6-phosphate (G6P), and structural basis of this process has not been well studied. MoTps1 (Magnaporthe oryzae Tps1) plays a critical role in carbon and nitrogen metabolism, but its structural information is unknown. Here we present the crystal structures of MoTps1 apo, binary (with UDPG) and ternary (with UDPG/G6P or UDP/T6P) complexes. MoTps1 consists of two modified Rossmann-fold domains and a catalytic center in-between. Unlike Escherichia coli OtsA (EcOtsA, the Tps1 of E. coli), MoTps1 exists as a mixture of monomer, dimer, and oligomer in solution. Inter-chain salt bridges, which are not fully conserved in EcOtsA, play primary roles in MoTps1 oligomerization. Binding of UDPG by MoTps1 C-terminal domain modifies the substrate pocket of MoTps1. In the MoTps1 ternary complex structure, UDP and T6P, the products of UDPG and G6P, are detected, and substantial conformational rearrangements of N-terminal domain, including structural reshuffling (β3–β4 loop to α0 helix) and movement of a ‘shift region' towards the catalytic centre, are observed. These conformational changes render MoTps1 to a ‘closed' state compared with its ‘open' state in apo or UDPG complex structures. By solving the EcOtsA apo structure, we confirmed that similar ligand binding induced conformational changes also exist in EcOtsA, although no structural reshuffling involved. Based on our research and previous studies, we present a model for the catalytic process of Tps1. Our research provides novel information on MoTps1, Tps1 family, and structure-based antifungal drug design.

Structures of trehalose-6-phosphate synthase, Tps1, from the fungal pathogenCryptococcus neoformans: a target for novel antifungals

“…Both lobes are spanned by an α-helix, formed by residues 572-603 (Figure 2D). Each domain contains a modified Rossman fold that is characteristic of the retaining glycosyltransferase family (40, 51) (Figure 2D), and similar to the published CaTps1 and CaTps1-like N-terminal domain of CaTps2 structures (Supplemental Figure 5) (34,41,43). A common feature that is observed in these substrate-free structures is a lack of density in portions of the N-terminus, suggestive of conformational flexibility in the absence of ligands.…”

“…Inspection of the Tps1 crystal structures from Candida albicans (40), Aspergillus fumigatus (40), E. coli (37, 38), Streptomyces venezuelae (34) and Magnaporthe oryzae (43) and the catalytically inactive Tps1-like N-terminal domain of C. albicans Tps2 (41) revealed that Tps1 most likely exists as a homo-tetramer. To determine if subunits of the Cryptococcus neoformans var.…”

Physiological and genomic insights into abiotic stress of halophilic archaeon Natrinema altunense 4.1R isolated from a saline ecosystem of Tunisian desert

“…7A). The template used was the trehalose-6-phosphate synthase (PDB 6JBR) from Pyricularia oryzae (Wang et al 2019). The identity and coverage of both proteins were 32.66 and 77% respectively.…”

In Silico Inhibitability of Copper Carbenes and Silylenes against Rhizoctonia solani and Magnaporthe oryzae

“…In particular, the latter is an essential step for the penetration of M. oryzae into host plants. Also, the synthesis of melanin is critically dependent on the activity of an enzymatic superfamily called glycosyltransferase, especially trehalose-6-phosphate synthase [7].…”