Algorithms ; Carrier Proteins ; chemistry ; Crystallography, X-Ray ; Humans ; Magnetic Resonance Spectroscopy ; Molecular Dynamics Simulation ; Nuclear Proteins ; chemistry ; Principal Component Analysis ; Protein Structure, Tertiary ; Proteins ; chemistry ; Scattering, Small Angle ; X-Ray Diffraction ; methods

Objective To investigate the changes of C1q tumor necrosis factor-related protein-12(CTRP12)levels in serum of the pa-tients with acute myocardial infarction(AMI)before and after percutaneous coronary intervention(PCI),and explore its clinical sig-nificance.Methods A total of 50 patients with AMI who underwent emergency PCI and 35 patients with normal coronary angiography results in Danyang People's Hospital from November 2021 to October 2022 were enrolled.The CTRP12 levels in peripheral venous ser-um were compared between the two groups.The levels of serum CTRP12 levels were measured before,during and on the 3rd,5th and 7th day after PCI.The serum CTRP12 levels in culprit coronary ostium and peripheral vein were compared.CTRP12 levels in peripher-al venous serum were compared at different time points after PCI.The severity of coronary artery disease was evaluated by SYNTAX score system,and the AMI patients were divided into two groups:SYNTAX score ≤22 and SYNTAX score＞22.The serum CTRP12 levels were compared between the two groups and before and after PCI.The correlation between CTRP12 and age,body mass index(BMI),fasting blood glucose,blood lipid and other factors was analyzed.The influencing factors of the severity of coronary artery le-sions were analyzed by logistic regression.Results The serum CTRP12 level in the patients with AMI was significantly lower than that in healthy controls(P＜0.05).There was no significant difference between the serum CTRP12 levels between preoperative peripheral vein and intraoperative culprit coronary orifice(P＞0.05).Compared with that before PCI,the serum CTRP12 level was lower on the 3rd day after PCI(P＜0.05),and increased on the 5th and 7th days after PCI,but no statistically significant difference was found(P＞0.05).Compared with those on the 3rd day after PCI,the serum CTRP12 levels were increased on the 5th and 7th day after PCI,but no statistically significant differences were found(all P＞0.05).Compared with that in the SYNTAX≤22 group,the CTRP12 levels were significantly lower than those before PCI and on the 3rd day after PCI(all P＜0.05),while there was no significant difference on the 5th and 7th day after PCI in SYNTAX＞22 group(all P＞0.05).CTRP12 was negatively correlated with the level of total cholesterol(TC)and positively correlated with high-density lipoprotein cholesterol(HDL-C).Univariate logistic regression analysis showed that CTRP12 was an independent influencing factor for the severity of coronary artery disease in the patients with AMI(β=-1.671,OR=0.188,P＜0.05).After adjusting for the effects of age,gender,BMI,smoking,hypertension,diabetes,fasting blood glucose,total cholesterol(TC),triglyceride(TG),HDL-C and low-density lipoprotein cholesterol(LDL-C),CTRP12 was still an independent in-fluencing factor for the severity of coronary artery disease in the patients with AMI(β=-3.441,OR=0.032,P＜0.05).Conclusion The serum CTRP12 level was significantly decreased in the patients with AMI before PCI,and showed continuous decline on the 3rd day after PCI,but increased on the 5th and 7th day after PCI.CTRP12 should be an independent influencing factor for the severity of coronary artery disease in the patients with AMI.

Mitophagy is an essential intracellular process that eliminates dysfunctional mitochondria and maintains cellular homeostasis. Mitophagy is regulated by the post-translational modification of mitophagy receptors. Fun14 domain-containing protein 1 (FUNDC1) was reported to be a new receptor for hypoxia-induced mitophagy in mammalian cells and interact with microtubule-associated protein light chain 3 beta (LC3B) through its LC3 interaction region (LIR). Moreover, the phosphorylation modification of FUNDC1 affects its binding affinity for LC3B and regulates selective mitophagy. However, the structural basis of this regulation mechanism remains unclear. Here, we present the crystal structure of LC3B in complex with a FUNDC1 LIR peptide phosphorylated at Ser17 (pS), demonstrating the key residues of LC3B for the specific recognition of the phosphorylated or dephosphorylated FUNDC1. Intriguingly, the side chain of LC3B Lys49 shifts remarkably and forms a hydrogen bond and electrostatic interaction with the phosphate group of FUNDC1 pS. Alternatively, phosphorylated Tyr18 (pY) and Ser13 (pS) in FUNDC1 significantly obstruct their interaction with the hydrophobic pocket and Arg10 of LC3B, respectively. Structural observations are further validated by mutation and isothermal titration calorimetry (ITC) assays. Therefore, our structural and biochemical results reveal a working model for the specific recognition of FUNDC1 by LC3B and imply that the reversible phosphorylation modification of mitophagy receptors may be a switch for selective mitophagy.
Crystallography, X-Ray ; Membrane Proteins ; chemistry ; metabolism ; Microtubule-Associated Proteins ; chemistry ; metabolism ; Mitochondrial Degradation ; Mitochondrial Proteins ; chemistry ; metabolism ; Peptides ; chemistry ; metabolism ; Phosphorylation ; Protein Structure, Quaternary

Objective To optimize the culture and fermentation conditions of the Penicillium aurantiocandidum Z12 strain, a fungal strain with molluscicidal actions against Oncomelania hupensis, so as to provide the basis for the research and development of molluscicidal active substances from the P. aurantiocandidum Z12 strain and its fermentation broth and large-scale fermentation. Methods The carbon source, nitrogen source and mineral salts were identified in the optimal culture medium for the P. aurantiocandidum Z12 strain with a single-factor experiment to determine the best fermentation condition for the P. aurantiocandidum Z12 strain. Factors that significantly affected the growth of the P. aurantiocandidum Z12 strain were identified using the Plackett-Burman design, and the best range of each factor was determined using the steepest climb test. Response surface analyses of temperature, pH value, seeding amount and liquid-filling quantity were performed using the Box-Behnken design to create a regression model for fermentation of the P. aurantiocandidum Z12 strain to identify the optimal culture medium. Results Single-factor experiment preliminarily identified the best culture medium and conditions for the P. aurantiocandidum Z12 strain as follows: sucrose as the carbon source at approximately 20 g/L, tryptone as the nitrogen source at approximately 5 g/L, K₂HPO₄ as the mineral salt at approximately 5 g/L, initial pH at approximately 8, temperature at approximately 28 °C, seeding amount at approximately 6%, and liquid-filling quantity at approximately 50 mL/100 mL. Plackett-Burman design showed that factors that significantly affected the growth of the P. aurantiocandidum Z12 strain included temperature (t = −5.28, P < 0.05), seeding amount (t = 5.22, P < 0.05), pH (t = −4.30, P < 0.05) and liquid-filling quantity (t = −4.39, P < 0.05). Steepest climb test showed the highest mycelial growth at pH of 7.5, seeding amount of 8%, and liquid-filling quantity of 40 mL/100 mL, and this condition was selected as the central point of response surface analysis for the subsequent optimization of fermentation conditions. Response surface analyses using the Box-Behnken design showed that the optimal conditions for fermentation of the P. aurantiocandidum Z12 strain included sucrose at 15 g/L, tryptone at 5 g/L, K₂HPO₄ at 5 g/L, temperature at 28.2 °C, pH at 7.5, seeding amount at 10%, and liquid-filling quantity at 35.8 mL/100.0 mL, resulting in 0.132 g yield of the P. aurantiocandidum Z12 strain. Conclusion The optimal culture condition for the P. aurantiocandidum Z12 strain has been identified, and the optimized culture medium and fermentation condition may effectively improve the fermentation yield of the P. aurantiocandidum Z12 strain.