Structure and function of African swine fever virus proteins: Current understanding

Figures

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  Figure 1. Schematic diagram of the ASFV structure. ASFV is composed of an external envelope, outer capsid, inner membrane, inner capsid, and nucleoid.

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  Figure 2. Schematic diagram of the ASFV pS273R structure. (A) pS273R catalyzes the hydrolysis of pp220 to p5, p34, p14, p37, and p150, and pp62 to p15, p35, and p8. (B) The pS273R protein consists of an “arm domain” (red) and a “core domain” (dark blue; Li et al., 2020).

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  Figure 3. Schematic diagram of the ASFV pA104R structure. (A) The dimer structure of the pA104R protein. Gray: protomer 1; light red: protomer 2. (B) Distribution of α-helices and β-sheets in the pA104R protomer.

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  Figure 4. Schematic diagram of the ASFV p15 structure. (A) The trimeric structure of the p15 protein. Orange: protomer 1; green: protomer 2; pink: protomer 3. (B) Distribution of α-helices and β-sheets in the p15 proteome.

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  Figure 5. (A) The capping mechanism of mRNA involved in pNP868R. First, the triphosphatase (TPase) hydrolyses the γ-phosphate of the nascent RNA (pppNp-RNA, in which N denotes the first transcribed nucleotide and p denotes a phosphate group) to yield a diphosphate RNA (ppNp-RNA) and inorganic phosphate (Pi). Then, guanylyltransferase (GTase) reacts with the α-phosphate of GTP (Gppp), releasing pyrophosphate (PPi) and forming a covalent enzyme–guanylate intermediate (Gp–GTase). The GTase then transfers the GMP molecule (Gp) to the 5′-diphosphate RNA to create GpppNp-RNA. In the final step (guanine-N7)-methyltransferase (N7MTase) transfers the methyl group from S-adenosyl-l-methionine (AdoMet) to the cap guanine to form the cap-0 structure, with the 7-methyl-GpppNp (m7GpppNp) releasing S-adenosyl-l-homocysteine (AdoHcy) as a by-product (Decroly et al., 2011). (B) Schematic diagram of the ASFV pNP868R protein structure, showing α-helices and β-sheets within the structure (Du et al., 2020).

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  Figure 6. Schematic diagram of ASFV g5Rp structure. (A) g5Rp consists of two protomers “back to back,” protomer 1 is in dark yellow and protomer 2 is in cyan (Yang et al., 2022). (B) Nudix domain (dark blue), the helical domain (yellow), and the Nudix motif of g5Rp (orange). (C) The α-helices and β-sheets of the g5Rp protomer.

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  Figure 7. (A) Schematic diagram of ASFV A179L and BH3 complex structures (Banjara et al., 2019). (B) A224L and A179L of ASFV inhibit apoptosis of infected cells (Dixon et al., 2017). ASFV A224L and A179L are shown as green hexagons. ASFV A179L Bcl-2 family proteins bind to and inhibit several pro-apoptotic proteins with a BH3 motif. A224L IAP family proteins bind to and inhibit caspase 3 and activate the nuclear factor Kappa-light chain enhancer of activated B cell (NF-κB) signaling, thereby increasing the expression of anti-apoptotic genes including cFLIP, cIAP2, and C-rel (Dixon et al., 2017).

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  Figure 8. (A) The trimeric structure of the p72 protein (Wang et al., 2019). Deep yellow: protomer 1; lavender: protomer 2; cyan: protomer 3. (B) Diagram of the p72 monomer. The domains base, JR1 (jelly roll 1), JR2 (jelly roll 2), and ER1 to ER4 are shown (Wang et al., 2019). (C) Diagram of the interaction of p72 with H240R, M1249L, p17, and p49 (Wang et al., 2019).