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Chemical modifications on histones constitute a key mechanism for gene regulation in chromatin context. Recently, histone lysine β-hydroxybutyrylation (Kbhb) was identified as a new form of histone acylation that connects starvation-responsive metabolism to epigenetic regulation. Sirtuins are a family of NAD+-dependent deacetylases. Through systematic profiling studies, we show that human SIRT3 displays class-selective histone de-β-hydroxybutyrylase activities with preference for H3 K4, K9, K18, K23, K27, and H4K16, but not for H4 K5, K8, K12, which distinguishes it from the Zn-dependent HDACs. Structural studies revealed a hydrogen bond-lined hydrophobic pocket favored for the S-form Kbhb recognition and catalysis. β-backbone but not side chain-mediated interactions around Kbhb dominate sequence motif recognition, explaining the broad site-specificity of SIRT3. The observed class-selectivity of SIRT3 is due to an entropically unfavorable barrier associated with the glycine-flanking motif that the histone Kbhb resides in. Collectively, we reveal the molecular basis for class-selective histone de-β-hydroxybutyrylation by SIRT3, shedding lights on the function of sirtuins in Kbhb biology through hierarchical deacylation.

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Coal gangue spontaneous combustion is a serious catastrophe associated with mining activities. Generally, the areas of coal gangue spontaneous combustion are regions of tremendous heat accumulation. Mastering the regularity of deep temperature distribution and eliminating internal heat is an effective method to control spontaneous combustion. In this study, using self-developed heat pipe (HP) and intelligent cloud monitoring software, three sets of single pipe experiments were conducted in different temperature areas of the coal gangue dump in Yinying Coal Mine. A fitted model between shallow and deep temperatures was established using the least squares method to perform goodness-of-fit tests and significance analysis, and to analyze the internal temperature variation under the action of an HP. The results show that the quadratic model fits better and the regression is significant, and can be used as an empirical regression formula for the shallow temperature estimation of the deep temperature. The temperature was clearly suppressed by the HP, and the average cooling range reaches 21.44% within 700 h. However, the temperature of the control group without an HP continued to rise by 8%. In the three experimental groups, the effective control radius of the single HP was 3 m. The best cooling was achieved when the gangue depth was 1 to 4 m and the temperature was between 90 °C and 450 °C. The study shows that the HP has a great effect on thermal removal and inhibits spontaneous combustion of the gangue. In addition, this paper also provides a theoretical basis for the technology of HP treatment of spontaneous combustion gangue dumps.

Coal gangue in long-term accumulation will often appear spontaneous combustion phenomenon. Generally, the disaster caused by it has always been one of the serious problems threatening the health of residents in the mining area. Master the regularity of deep temperature distribution and eliminate the internal heat is an effective method to control the spontaneous combustion. In this study, using the self-developed heat pipe (HP) and intelligent cloud monitoring software, three groups of single pipe experiments were carried out in different temperature areas of the coal gangue dump in Yinying Coal Mine, to analyze the internal temperature variation under the action of HP. The results show that the temperature is obviously restrained by the HP, and the average cooling range reaches 21.44% within 700h. However, the temperature of the control group without HP continued to rise by 8%. In the three groups of experiments, the effective control radius of single HP is 3m. When the depth of gangue is 1 ~ 4m and the temperature between 90 ℃ ~ 450 ℃, the cooling effect is the best. It revealed that the HP had a substantial effect on thermal removal and inhibited spontaneous coal gangue combustion. In addition, this paper provides a theoretical basis for the HP treatment of spontaneous combustion coal gangue dumps technology.