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ABSTRACT Blast disease caused by Magnaporthe oryzae threatens rice production worldwide, and chemical control is one of the main methods of its management. The high mutation rate of the M. oryzae genome results in drug resistance, which calls for novel fungicide targets. Fungal proteins that function during the infection process might be potential candidates, and Mps1 (M. oryzae mitogen-activated protein kinase 1) is such a protein that plays a critical role in appressorium penetration of the plant cell wall. Here, we report the structure-aided identification of a small-molecule inhibitor of Mps1. High-throughput screening was performed with Mps1 against a DNA-encoded compound library, and one compound, named A378-0, with the best performance was selected for further verification. A378-0 exhibits a higher binding affinity than the kinase cosubstrate ATP and can inhibit the enzyme activity of Mps1. Cocrystallization of A378-0 with Mps1 revealed that A378-0 binds to the catalytic pocket of Mps1, while the three ring-type substructures of A378-0 constitute a triangle that squeezes into the pocket. In planta assays showed that A378-0 could inhibit both the appressorium penetration and invasive growth but not the appressorium development of M. oryzae, which is consistent with the biological function of Mps1. Furthermore, A378-0 exhibits binding and activity inhibition abilities against Mpk1, the Mps1 ortholog of the soilborne fungal pathogen Fusarium oxysporum. Collectively, these results show that Mps1 as well as its orthologs can be regarded as fungicide targets, and A378-0 might be used as a hit compound for the development of a broad-spectrum fungicide. IMPORTANCE M. oryzae is the causal agent of rice blast, one of the most devastating diseases of cultivated rice. Chemical control is still the main strategy for its management, and the identification of novel fungicide targets is indispensable for overcoming existing problems such as drug resistance and food safety. With a combination of structural, biochemical, and in planta assays, our research shows that Mps1 may serve as a fungicide target and confirms that compound A378-0 binds to Mps1 and possesses bioactivity in inhibiting M. oryzae virulence. As fungal orthologs of Mps1 are conserved, A378-0 may serve as a hit for broad-spectrum fungicide development, as evidenced with Mpk1, the Mps1 ortholog of F. oxysporum. Additionally, A378-0 contains a novel chemical scaffold that has not been reported in approved kinase inhibitors, suggesting its potential to be considered the basis for the development of other kinase inhibitors.

Background: Targeting the CD47/SIRPα signaling pathway represents a novel approach to enhance anti-tumor immunity. However, the crystal structure of the CD47/SIRPα has not been fully studied. This study aims to analyze the structure interface of the complex of CD47 and IMM01, a novel recombinant SIRPα-Fc fusion protein. Methods: IMM01-Fab/CD47 complex was crystalized, and diffraction images were collected. The complex structure was determined by molecular replacement using the program PHASER with the CD47-SIRPαv2 structure (PDB code 2JJT) as a search model. The model was manually built using the COOT program and refined using TLS parameters in REFMAC from the CCP4 program suite. Results: Crystallization and structure determination analysis of the interface of IMM01/CD47 structure demonstrated CD47 surface buried by IMM01. Comparison with the literature structure (PDB ID 2JJT) showed that the interactions of IMM01/CD47 structure are the same. All the hydrogen bonds that appear in the literature structure are also present in the IMM01/CD47 structure. These common hydrogen bonds are stable under different crystal packing styles, suggesting that these hydrogen bonds are important for protein binding. In the structure of human CD47 in complex with human SIRPα, except SER66, the amino acids that form hydrogen bonds are all conserved. Furthermore, comparing with the structure of PDB ID 2JJT, the salt bridge interaction from IMM01/CD47 structure are very similar, except the salt bridge bond between LYS53 in IMM01 and GLU106 in CD47, which only occurs between the B and D chains. However, as the side chain conformation of LYS53 in chain A is slightly different, the salt bridge bond is absent between the A and C chains. At this site between chain A and chain C, there are a salt bridge bond between LYS53 (A) and GLU104 (C) and a salt bridge bond between HIS56 (A) and GLU106 (C) instead. According to the sequence alignment results of SIRPα, SIRPβ and SIRPγ in the literature of PDB ID 2JJT, except ASP100, the amino acids that form common salt bridge bonds are all conserved. Conclusion: Our data demonstrated crystal structure of the IMM01/CD47 complex and provides a structural basis for the structural binding interface and future clinical applications.

First principles investigation and Hirshfeld surface analysis of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) crystals have been carried out. The geometrical and electronic structures of TATB molecules in the crystal and gas phases were compared. The Hirshfeld surface analysis of the TATB crystal structure shows that the intermolecular H⋯O interactions make important contributions in stabilizing the TATB crystal, while other intermolecular H⋯N and H⋯C interactions, O⋯O, N⋯O, C⋯O, and C⋯N close contacts also make contributions. QTAIM analyses of the intermolecular interactions in the molecular pairs confirm the presence of these intermolecular interactions based on Hirshfeld surface analyses, indicating that these intermolecular interactions play important roles in the crystal. The reason why the TATB crystal adopts a high energy conformer in which the NO2 and NH2 groups are coplanar with the benzene ring is elaborated. The cooperativity between hydrogen bonding and π⋯π interactions in the TATB crystal is verified and illustrated. [ABSTRACT FROM AUTHOR]

Trehalose-6-phosphate (T6P) synthase (Tps1) catalyzes the formation of T6P from UDPglucose (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 Rossmannfold 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. [ABSTRACT FROM AUTHOR]

We prepared a series of pressed powder tablets and chalcopyrite glass standards to correct mass bias when using standard–sample bracketing for in situ sulfur isotope measurements. A femtosecond laser ablation coupled multi-collector inductively coupled plasma mass spectrometry (fsLA-MC-ICP-MS) method was used to determine the sulfur isotope composition of these standards. Chalcopyrite glass (YN411-m) was prepared by quickly quenching the fused chalcopyrite, which was melted at 1000 °C under a protective N2 atmosphere. Multiple experiments were conducted for homogeneity testing of YN411-m by fsLA-MC-ICP-MS and the external precision was 0.28‰ (n = 35). Mineral particles, pressed powder tablets, and chalcopyrite glass were used as bracketing standards when determining the δ34S of a natural chalcopyrite (GC). The results showed that the concentration, elemental composition, and crystal structure caused the matrix effect. Considering practicability, the melted glass was a more appropriate standard than the pressed powder tablet. We also found that the carrier gas flow rate, laser fluence, and spot size impacted the regularity of results. Therefore, we can obtain accurate δ34S by adjusting the laser and MC-ICP-MS parameters when using non-matrix matching standards. Furthermore, fsLA-MC-ICP-MS is advantageous for in situ sulfur isotope measurement because the sensitivity can be improved and it dramatically improves the spatial resolution (10–20 μm), which can be used to explain the origin of multi-genesis deposits by analyzing smaller mineral micro-areas, especially mineral fracture-filling sulfides later in mineralization. [ABSTRACT FROM AUTHOR]

Two Zn(II)-containing complexes based on fluconazole, {[Zn(HFlu)2(IPA)]·9H2O}n(1), {[Zn(HFlu)2(OH-BDC)]·8H2O}n(2) (HFlu = fluconazole; 2-(2,4-difluoro- phenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol; H2IPA = isophthalic acid; OH-H2BDC = 5-hydroxyisophthalic acid) have been synthesized and structurally characterized. Complex1and2are both a one-dimensional (1D) tubular structure with the distorted dinuclear zinc rectangular-shaped cavity, and large free water molecules involved in strong O‒H···O and O‒H···N hydrogen bonds are accommodated in the 1D tubular structure. The thermal stabilities and photoluminescent properties of the coordination polymers have also been investigated. [ABSTRACT FROM AUTHOR]

C14H13NO, monoclinic, P21/n (no. 14), a = 9.2770(7) Å, b = 8.4582(6) Å, c = 13.4430(12) Å, β = 98.199(8)°, V = 1044.05(14) Å3, Z = 4, Rgt(F) = 0.0484, wRref(F2) = 0.1151, T = 100 K. [ABSTRACT FROM AUTHOR]

Two new metal-organic frameworks, namely [Cd(3-NO2-bdc)(2,2′-bpy)(H2O)•H2O]2(1) and[Ni(3-NO2-bdc)(4,4′-bpy)H2O]n(2) (where 3-NO2-bdcH2= 3-nitro-1,2-benzenedicarboxylic acid, 2,2′-bpy = 2,2′-bipyridine, 4,4′-bpy = 4,4′-bipyridine), have been synthesized and structurally characterized. Complex 1 is a 0-dimensional (0D) framework, but face-to-face π-π stacking interactions and O–H···O hydrogen bonds extend these molecules into a 3D supramolecular framework. X-ray structure analysis reveals that complexes 2 exhibit a 2-dimensional (2D) network structure. Also, IR spectra, fluorescence properties, thermal decomposition process, and powder X-ray diffraction of the complexes were investigated. [ABSTRACT FROM PUBLISHER]