The amino acid residue E96 of Ghd8 is crucial for the formation of the flowering repression complex Ghd7-Ghd8-OsHAP5C in rice.

Ghd7 is an important gene involved in the photoperiod flowering pathway in rice. A Ghd7-involved transcriptional regulatory network has been established, but its translational regulatory pathway is poorly understood. The mutant suppressor of overexpression of Ghd7 (sog7) was identified from EMS-induced mutagenesis on the background of ZH11 overexpressing Ghd7. MutMap analysis revealed that SOG7 is allelic to Ghd8 and delayed flowering under long-day (LD) conditions. Biochemical assays showed that Ghd8 interacts with OsHAP5C and Ghd7 both in vivo and in vitro. Surprisingly, a point mutation E96K in the α2 helix of the Ghd8 histone fold domain (HFD) destroyed its ability to interact with Ghd7. The prediction of the structure shows that mutated amino acid is located in the interaction region of CCT/NF-YB/YC complexes, which alter the structure of α4 of Ghd8. This structural difference prevents the formation of complex NF-YB/YC. The triple complex of Ghd8-OsHAP5C-Ghd7 directly bound to the promotor of Hd3a and downregulated the expression of Ehd1, Hd3a and RFT1, and finally resulted in a delayed heading. These findings are helpful in deeply understanding the Ghd7-involved photoperiod flowering pathway and promote the elucidation of rice heading.

Structure-Based Design of a Br Halogen Bond at the Complex Interface of the Human Placental HtrA1 PDZ Domain with Its Heptapeptide Ligand.

The shock-induced serine protease HtrA1 is a potential regulator of human placenta development during pregnancy. The protein contains a functional PDZ domain that has been solved in complex with a phage display-derived heptapeptide: Asp-6 Ser-5 Arg-4 Ile-3 Trp-2 Trp-1 Val0 . In this study, a rationally designed halogen bond was introduced to the domain-peptide complex based on its NMR structure in solution. We computationally compared the stabilization energies and hindrance effects due to the presence of different halogens X (X = F, Cl, Br, or I), using a hybrid quantum mechanics/molecular mechanics (QM/MM) approach, and found that the Br atom could considerably promote the peptide binding free energy (ΔΔG = -5.2 kcal/mol). Fluorescence assays confirmed that the peptide affinity to the HtrA1 PDZ domain was improved by approximately sevenfold upon bromination. Structural analysis identified a geometrically perfect halogen bond between the Br atom of the peptide Trp-1 residue and the carbonyl O atom of the HtrA1 Ile385 residue, with a bond length and an interaction energy of d = 3.20 Å and ΔE = -3.7 kcal/mol, respectively.

Discovery of N-(3-((7H-purin-6-yl)thio)-4-hydroxynaphthalen-1-yl)-sulfonamide derivatives as novel protein kinase and angiogenesis inhibitors for the treatment of cancer: Synthesis and biological evaluation. Part III.

A novel series of N-(3-((7H-purin-6-yl)thio)-4-hydroxynaphthalen-1-yl)-sulfonamides were designed and synthesized. Biological characterization revealed that several compounds exerted enhanced anti-proliferative activity against human umbilical vein endothelial cells (HUVECs) and several cancer cell lines and high specific protein kinase and angiogenesis inhibitory activities. Compared with our previously synthesized compounds, the substitution of sulfonamide structure for amide fragment played an essential role for the advance of inhibitory activities. In addition, the replacement of 1H-1,2,4-triazole ring by 7H-purine did not result in obvious decrease of inhibition efficacy, indicating that the sulfonamide structure contributes even more to the inhibition efficacy than the 1H-1,2,4-triazole ring. Among these compounds, compound 9n demonstrated comparable in vitro antiangiogenic activities to pazopanib in both HUVEC tube formation assay and the rat thoracic aorta rings (TARs) test. Meanwhile, compound 9n was identified to inhibit Akt1 (IC50=1.73 µM) and Abl tyrosine kinase (IC50=1.53 µM) effectively.

Discovery of 4-amino-2-(thio)phenol derivatives as novel protein kinase and angiogenesis inhibitors for the treatment of cancer: synthesis and biological evaluation. Part II.

A novel series of 4-amino-2-(thio)phenol derivatives were well synthesized. The preliminary biological test revealed that several compounds displayed high specific protein kinase and angiogenesis inhibitory activities compared with previous work mainly because of the substitution of sulfonamide structure for amide fragment. Among which, compound 5i was identified to inhibit protein kinase B/AKT (IC50 = 1.26 µM) and ABL tyrosine kinase (IC50 = 1.50 µM) effectively. Meanwhile, compound 5i demonstrated competitive in vitro antiangiogenic activities to Pazopanib in both human umbilical vein endothelial cell (HUVEC) tube formation assay and the rat thoracic aorta rings test.

Synthesis and biological evaluation of N-(4-hydroxy-3-mercaptonaphthalen-1-yl)amides as inhibitors of angiogenesis and tumor growth.

A series of N-(4-hydroxy-3-mercaptonaphthalen-1-yl)amides were synthesized and investigated for their in vitro antiangiogenic activity. Among these compounds, 6d, which possesses an ortho-nitro group at the benzene ring, exhibited potent inhibitory effect on the proliferation of HUVECs, A549, K562, PC-3, HCT116, MDA-MB-231 and MCF-7 cells (IC50 = 5.34, 40.53, 10.81, 52.52, 10.19, 21.37 and 2.81 µM, respectively). Meanwhile, compound 6d inhibited in vitro angiogenesis markedly in both HUVECs tube formation assay and the rat thoracic aorta rings test. Further kinase assay study showed that compound 6d had good VEGFR2, ALK, AKT1 and ABL inhibitory activities and moderate EGFR and PDGFR-ß inhibitory activities. The data supports the further investigation of this class of compounds as potential antiangiogenic and anticancer agents.

Serological reports of human infections of H7 and H9 avian influenza viruses in northern China.

BACKGROUND: H7 and H9 subtype avian influenza viruses pose a similar threat to humans as H5 virus. OBJECTIVES: This study aims to identify the potential existence of H7 and H9 avian influenza infections in farmers and in poultry workers in northern China regions with highly pathogenic avian influenza (HPAI) H5N1 outbreaks. STUDY DESIGN: Sera were collected from farmers in Xinjiang Uygur autonomous region and Liaoning province and poultry workers in Shandong province. Sera from healthy residents in Shanxi province were used as the controls. H7 and H9 virus infections were examined by hemagglutination inhibition (HI) assay using horse erythrocytes. The titer equal to or greater than 1:160 was considered positive. RESULTS: A total of 583 sera collected from farmers in Xinjiang were tested, and 10 (1.7%) were positive for H9 virus infection. Out of 200 sera collected from Liaoning, two (1.0%) were infected by H9 virus. No H7 virus infection was detected in the above serum samples. Neither H7 nor H9 virus infection was identified in 277 poultry workers of Shandong and in 407 residents of Shanxi. CONCLUSIONS: Although H9 virus infection was limited in farmers from Xinjiang and Liaoning, a public health alert is needed as novel pandemic influenza strains may develop unnoticed given the presence of subclinical infections, and the possibility of re-assortment with prevailing H5N1 virus in these regions.