1.Analysis of Risk Factors and Establishment of Prediction Model for Turbidity Toxicity Accumulation Syndrome in Patients with Chronic Atrophic Gastritis
Yican WANG ; Chenggong ZHAO ; Pengli DU ; Jie WANG ; Yuxi GUO ; Haiyan BAI ; Yongli HUO ; Xiaomeng LANG ; Zheng ZHI ; Bolin LI ; Jianping LIU ; Yanru CAI ; Jianming JIANG ; Qian YANG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(10):288-295
ObjectiveThis paper aims to explore the risk factors for chronic atrophic gastritis (CAG) with turbidity toxin accumulation syndrome and establish a prediction model. MethodsClinical data of 180 patients with CAG who participated in the "clinical study of Xianglian Huazhuo Particles blocking CAG cancer transformation" of Hebei Sheng Zhong Yi Yuan from July 2021 to March 2022 were collected. After confounding factors were controlled by propensity score matching, patients were divided into a training set (namely dev) and a validation set (namely vad) in a seven to three ratio. The risk factors for CAG with turbidity toxin accumulation syndrome in the training set were investigated by using univariate Logistic regression analysis and least absolute shrinkage and selection operator (namely Lasso) regression algorithms. Subsequently, a model, named model 1se, was developed by using the training set data to predict the risk factors for CAG with turbidity toxin accumulation syndrome. The accuracy of the prediction model was assessed by using various methods, including the receiver operating characteristic (ROC) curve, Hosmer-Lemeshow test (H-L), calibration plot, and decision curve analysis (DCA). ResultsAge, body mass index (BMI), family history of cancer, job and life satisfaction, yellow and greasy fur with slippery pulse, and heavy body sensation were independent risk factors of the model. The prediction model showed excellent predictive value for both the training and validation sets. ConclusionThe established prediction model for CAG with turbidity toxin accumulation syndrome has high discrimination and excellent calibration, which could provide an excellent clinical basis for disease diagnosis and individualized treatment of patients.
2.Analysis of Risk Factors and Establishment of Prediction Model for Turbidity Toxicity Accumulation Syndrome in Patients with Chronic Atrophic Gastritis
Yican WANG ; Chenggong ZHAO ; Pengli DU ; Jie WANG ; Yuxi GUO ; Haiyan BAI ; Yongli HUO ; Xiaomeng LANG ; Zheng ZHI ; Bolin LI ; Jianping LIU ; Yanru CAI ; Jianming JIANG ; Qian YANG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(10):288-295
ObjectiveThis paper aims to explore the risk factors for chronic atrophic gastritis (CAG) with turbidity toxin accumulation syndrome and establish a prediction model. MethodsClinical data of 180 patients with CAG who participated in the "clinical study of Xianglian Huazhuo Particles blocking CAG cancer transformation" of Hebei Sheng Zhong Yi Yuan from July 2021 to March 2022 were collected. After confounding factors were controlled by propensity score matching, patients were divided into a training set (namely dev) and a validation set (namely vad) in a seven to three ratio. The risk factors for CAG with turbidity toxin accumulation syndrome in the training set were investigated by using univariate Logistic regression analysis and least absolute shrinkage and selection operator (namely Lasso) regression algorithms. Subsequently, a model, named model 1se, was developed by using the training set data to predict the risk factors for CAG with turbidity toxin accumulation syndrome. The accuracy of the prediction model was assessed by using various methods, including the receiver operating characteristic (ROC) curve, Hosmer-Lemeshow test (H-L), calibration plot, and decision curve analysis (DCA). ResultsAge, body mass index (BMI), family history of cancer, job and life satisfaction, yellow and greasy fur with slippery pulse, and heavy body sensation were independent risk factors of the model. The prediction model showed excellent predictive value for both the training and validation sets. ConclusionThe established prediction model for CAG with turbidity toxin accumulation syndrome has high discrimination and excellent calibration, which could provide an excellent clinical basis for disease diagnosis and individualized treatment of patients.
3.Investigating Effect of Xianglian Huazhuo Prescription on Cell Cycle and Proliferation in Rats with Chronic Atrophic Gastritis Through TGF-β1/Smads Signaling Pathway
Yican WANG ; Jie WANG ; Yirui CHENG ; Xiaojing LI ; Yibin MA ; Qiuhua LIU ; Ziwei LIU ; Yuxi GUO ; Pengli DU ; Yanru CAI ; Yao DU ; Zheng ZHI ; Bolin LI ; Qian YANG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(8):128-136
ObjectiveTo explore the potential mechanism of Xianglian Huazhuo prescription (XLHZ) in treating chronic atrophic gastritis (CAG) by regulating cell cycle and inhibiting proliferation, using bioinformatics technology and animal experiments. MethodsDifferential expressed genes (DEGs) related to CAG were screened using GEO database and GEO2R tool. Weighted gene co-expression network analysis (WGCNA) was employed to search for hub genes of CAG. These hub genes were intersected with cell cycle proliferation based on GeneCards database. Eenrichment analysis of the intersecting genes was performed to obtain signaling pathways and biological processes related to CAG. Protein protein interaction (PPI) analysis of genes was conducted using the Protein Interaction Platform (STRING) database to search the super hub gene (hub 2.0), and animal experiments were conducted for further validation. Fourteen of 70 male Wistar rats were randomly selected as the normal group, and the remaining 56 rats were prepared by the combined modeling method of "starvation disorder+N-methyl-N-nitro-N-nitrosoguanidine (MNNG) + sodium salicylate". The successfully modeled rats were randomly divided into the model group, XLHZ-H, XLHZ-M, and XLHZ-L groups (36, 18, 9 g·kg-1, respectively), and Morodan group (1.4 g·kg-1). Each group was given corresponding intervention for 60 days. Hematoxylin-eosin (HE) staining was used to observe the histopathological changes of gastric mucosa in rats. The ultrastructure of gastric mucosal tissue cells was observed by transmission electron microscopy. The relative expression levels of TGF-β1, Smad2 and Smad3 proteins, S/G2/M phase marker geminin and proliferation marker MCM2 were detected by Western blot in gastric mucosal tissue, and Spearman correlation analysis was performed. ResultsA total of 15 hub 2.0 genes were identified, including TGF-β1, suggesting the involvement of the TGF-β1 signaling pathway in the CAG pathogenesis. Compared with the normal group, the expressions of TGF-β1, Smad2, geminin and MCM2 proteins in the gastric mucosa tissue of the model group were increased (P<0.05), and the expression of Smad3 protein was decreased (P<0.05). Compared with the model group, the expressions of TGF-β1 and geminin in the gastric mucosa were decreased in the drug groups (P<0.05). The XLHZ-M group, XLHZ-H group and Morodan group had significantly decreased protein expression of Smad2 and MCM2 (P<0.05). The protein expression of Smad3 was significantly increased in XLHZ-M, XLHZ-H, and Morodan groups (P<0.05). Spearman correlation analysis showed that Smad3 was negatively correlated with other indicators, and positively correlated with other indicators (P<0.01). ConclusionXLHZ may inhibit TGF-β1/Smads signaling pathway, regulate cell cycle, and inhibit proliferation in the treatment of CAG.
4.Investigating Effect of Xianglian Huazhuo Prescription on Cell Cycle and Proliferation in Rats with Chronic Atrophic Gastritis Through TGF-β1/Smads Signaling Pathway
Yican WANG ; Jie WANG ; Yirui CHENG ; Xiaojing LI ; Yibin MA ; Qiuhua LIU ; Ziwei LIU ; Yuxi GUO ; Pengli DU ; Yanru CAI ; Yao DU ; Zheng ZHI ; Bolin LI ; Qian YANG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(8):128-136
ObjectiveTo explore the potential mechanism of Xianglian Huazhuo prescription (XLHZ) in treating chronic atrophic gastritis (CAG) by regulating cell cycle and inhibiting proliferation, using bioinformatics technology and animal experiments. MethodsDifferential expressed genes (DEGs) related to CAG were screened using GEO database and GEO2R tool. Weighted gene co-expression network analysis (WGCNA) was employed to search for hub genes of CAG. These hub genes were intersected with cell cycle proliferation based on GeneCards database. Eenrichment analysis of the intersecting genes was performed to obtain signaling pathways and biological processes related to CAG. Protein protein interaction (PPI) analysis of genes was conducted using the Protein Interaction Platform (STRING) database to search the super hub gene (hub 2.0), and animal experiments were conducted for further validation. Fourteen of 70 male Wistar rats were randomly selected as the normal group, and the remaining 56 rats were prepared by the combined modeling method of "starvation disorder+N-methyl-N-nitro-N-nitrosoguanidine (MNNG) + sodium salicylate". The successfully modeled rats were randomly divided into the model group, XLHZ-H, XLHZ-M, and XLHZ-L groups (36, 18, 9 g·kg-1, respectively), and Morodan group (1.4 g·kg-1). Each group was given corresponding intervention for 60 days. Hematoxylin-eosin (HE) staining was used to observe the histopathological changes of gastric mucosa in rats. The ultrastructure of gastric mucosal tissue cells was observed by transmission electron microscopy. The relative expression levels of TGF-β1, Smad2 and Smad3 proteins, S/G2/M phase marker geminin and proliferation marker MCM2 were detected by Western blot in gastric mucosal tissue, and Spearman correlation analysis was performed. ResultsA total of 15 hub 2.0 genes were identified, including TGF-β1, suggesting the involvement of the TGF-β1 signaling pathway in the CAG pathogenesis. Compared with the normal group, the expressions of TGF-β1, Smad2, geminin and MCM2 proteins in the gastric mucosa tissue of the model group were increased (P<0.05), and the expression of Smad3 protein was decreased (P<0.05). Compared with the model group, the expressions of TGF-β1 and geminin in the gastric mucosa were decreased in the drug groups (P<0.05). The XLHZ-M group, XLHZ-H group and Morodan group had significantly decreased protein expression of Smad2 and MCM2 (P<0.05). The protein expression of Smad3 was significantly increased in XLHZ-M, XLHZ-H, and Morodan groups (P<0.05). Spearman correlation analysis showed that Smad3 was negatively correlated with other indicators, and positively correlated with other indicators (P<0.01). ConclusionXLHZ may inhibit TGF-β1/Smads signaling pathway, regulate cell cycle, and inhibit proliferation in the treatment of CAG.
5.Isolation of Mycobacterium monacense from lung tissue using mNGS technology: a case report and literature review
Ze SU ; Qing SUN ; Dong ZHANG ; Jie YI ; Juan DU ; Qiwen YANG ; Rui ZHANG
Chinese Journal of Laboratory Medicine 2025;48(11):1461-1464
The patient is a 63-year-old man with a history of chronic illness, presenting with intermittent low-grade fever, recurrent dry cough, and shortness of breath upon exertion. Lung CT showed a nodule in the left lung and a large mass in the right lung with liquefactive necrosis and an air-fluid level accompanied by pleural effusion. Laboratory findings showed significantly increasedf immunoglobulin G (IgG), IgG4, and total immunoglobulin E, along with a mild increase in eosinophils, and moderate elevations in erythrocyte sedimentation rate and high-sensitivity C-reactive protein. Malignant tumors, immunological, and hematological diseases were ruled out. Various antibiotic treatments were ineffective and the condition was recurrent. Conventional methods failed to identify the pathogen. Metagenomic next-generation sequencing (mNGS) technology was used to detect Mycobacterium monacense from lung tissue. Targeted antibiotic treatment was effective with no further episodes of low-grade fever and alleviation of dry cough symptoms. This case underscores the clinical significance of mNGS technology for the diagnosis and treatment of unexplained pulmonary infections, providing a useful reference for clinical diagnostic and treatment.
6.Epidemiological Analysis of Pathogens in Acute Respiratory Infections During the 2023-2024 Autumn-Winter Season in Beijing:A Case Series of 5556 Patients at Peking Union Medical College Hospital
Yan CAO ; Yu CHEN ; Jie YI ; Lingjun KONG ; Ziyi WANG ; Rui ZHANG ; Qi YU ; Yiwei LIU ; Maimaiti MULATIJIANG ; Chenglin YANG ; Yujie SUN ; Yingchun XU ; Qiwen YANG ; Juan DU
Medical Journal of Peking Union Medical College Hospital 2025;16(3):680-686
Objective To analyze the epidemiological characteristics of acute respiratory infections(ARIs)during the autumn-winter season in Beijing,providing evidence for the prevention,control,diagnosis,and treatment of ARIs.Methods A convenience sampling method was employed,enrolling patients who visited Peking Union Medical College Hospital(PUMCH)between September 2023 and February 2024 due to ARIs.Na-sopharyngeal swabs were collected,and real-time fluorescence quantitative PCR was used to detect six common respiratory pathogens[influenza A virus(FluA),influenza B virus(FluB),human rhinovirus(HRV),Myco-plasma pneumoniae(MP),respiratory syncytial virus(RSV),and adenovirus(ADV)],as well as SARS-CoV-2 infection.The distribution patterns of pathogen infections were analyzed.Results A total of 5556 eligible patients were included.The overall positivity rate for the six common respiratory pathogens was 63.7%,with sin-gle-pathogen positivity at 54.0%,dual-pathogen positivity at 8.9%,and triple or more pathogen positivity at 0.7%.The predominant pathogens detected were FluA(16.1%)and RSV(15.7%),followed by ADV(11.1%),MP(11.1%),HRV(10.0%),and FluB(10.0%).No significant difference in overall pathogen positivity was observed between genders.However,significant differences were found between autumn and winter(x2=34.617,P<0.001)and among pediatric,young/middle-aged,and elderly patients(x2=422.38,P<0.001).Specifically,MP(x2=8.647,P=0.003),FluA(x2=131.932,P<0.001),and HRV(x2=174.199,P<0.001)exhibited significantly higher positivity rates in autumn than in winter,whereas FluB was more prevalent in winter(x2=287.894,P<0.001).In pediatric patients,MP,RSV,HRV,and ADV positivity rates were significantly higher than in young/middle-aged and elderly patients(all P<0.001),whereas FluB was more common in young/middle-aged patients(both P<0.001).The positivity rates of the six common respiratory pathogens significantly declined during the SARS-CoV-2 epidemic period,exhibiting an asynchronous seasonal pattern.Conclusions The prevalence of respiratory pathogens in Beijing is associated with age and season.Tar-geted preventive measures should be implemented in different seasons and for key populations.
7.Diagnosis and treatment guideline for acute cervical spinal cord injury without fracture-dislocation in adults (version 2025)
Qingde WANG ; Tongwei CHU ; Jian DONG ; Liangjie DU ; Haoyu FENG ; Shunwu FAN ; Shiqing FENG ; Yanzheng GAO ; Yong HAI ; Da HE ; Dianming JIANG ; Jianyuan JIANG ; Bin LIN ; Bin LIU ; Baoge LIU ; Fang LI ; Feng LI ; Li LI ; Weishi LI ; Fangcai LI ; Xiaoguang LIU ; Hongjian LIU ; Yong LIU ; Zhongjun LIU ; Shibao LU ; Xuhua LU ; Keya MAO ; Xuexiao MA ; Yong QIU ; Limin RONG ; Jun SHU ; Yueming SONG ; Tiansheng SUN ; Yan WANG ; Zhe WANG ; Zheng WANG ; Bing WANG ; Linfeng WANG ; Yu WANG ; Qinghe WANG ; Jigong WU ; Hong XIA ; Guoyong YIN ; Jinglong YAN ; Wen YUAN ; Yong YANG ; Qiang YANG ; Cao YANG ; Jie ZHAO ; Jianguo ZHANG ; Yue ZHU ; Zezhang ZHU ; Yingjie ZHOU ; Zhongmin ZHANG ; Yan ZENG ; Dingjun HAO ; Baorong HE ; Wei MEI
Chinese Journal of Trauma 2025;41(3):243-252
Cervical spinal cord injury without fracture-dislocation (CSCIWFD) is referred to as a special type of cervical spinal cord injury characterized by traumatic spinal cord dysfunction and no significant bony structural abnormalities on imagines. Duo to the high risk of missed diagnosis during the initial consultation, CSCIWFD may lead to progressive neurological deterioration or even complete paralysis, severely impacting patients′ prognosis. Currently, there are no established consensuses over the diagnosis and treatment of CSCIWFD, such as the lack of evidence-based standards for indications of non-surgical treatment and risk of secondary neurological injury, as well as debates over the optimal timing for surgical intervention and indications for different surgical approaches. To address these issues, the Spine Trauma Group of the Orthopedic Branch of the Chinese Medical Doctor Association organized experts in the relevant fields to formulate Diagnosis and treatment guideline for acute cervical spinal cord injury without fracture- dislocation in adults ( version 2025) . Based on evidence-based medicine and the principles of scientific rigor and clinical applicability, the guidelines proposed 11 recommendations covering terminology, diagnosis, evaluation treatment, and rehabilitation, etc., aiming to standardize the management of CSCIWFD.
8.Guideline for the diagnosis and treatment of vertebral refracture after percutaneous vertebral augmentation in elderly patients with osteoporotic thoracolumbar compression fractures (version 2025)
Yong YANG ; Xiaoguang ZHOU ; Qixin CHEN ; Jian CHEN ; Jian DONG ; Liangjie DU ; Shunwu FAN ; Jin FAN ; Zhong FANG ; Haoyu FENG ; Shiqing FENG ; Haishan GUAN ; Aiguo GAO ; Yanzheng GAO ; Yong HAI ; Da HE ; Dengwei HE ; Haiyi HE ; Dianming JIANG ; Xuewen KANG ; Bin LIN ; Baoge LIU ; Changqing LI ; Fang LI ; Li LI ; Fangcai LI ; Weishi LI ; Xiaoguang LIU ; Hongjian LIU ; Xinyu LIU ; Yong LIU ; Zhongjun LIU ; Shibao LU ; Xuhua LU ; Fei LUO ; Yuhai MA ; Keya MAO ; Xuexiao MA ; Bin MENG ; Xu NING ; Limin RONG ; Hongxun SANG ; Jun SHU ; Tiansheng SUN ; Dasheng TIAN ; Zheng WANG ; Bing WANG ; Linfeng WANG ; Qingde WANG ; Qinghe WANG ; Lan WEI ; Jigong WU ; Baoshan XU ; Youjia XU ; Guoyong YIN ; Jinglong YAN ; Feng YAN ; Cao YANG ; Huilin YANG ; Qiang YANG ; Bin ZHAO ; Jie ZHAO ; Yue ZHU ; Jianguo ZHANG ; Wenzhi ZHANG ; Zhongmin ZHANG ; Zhaomin ZHENG ; Yan ZENG ; Baorong HE ; Wei MEI
Chinese Journal of Trauma 2025;41(7):613-626
Vertebral refracture following percutaneous vertebral augmentation (PVA) is commonly seen in elderly patients with osteoporotic thoracolumbar compression fractures (OTLCF). It can lead to recurrent pain, loss of vertebral height, progression of kyphosis, and even neurological dysfunction, significantly impairing patients′ quality of life. Current diagnosis and treatment face multiple challenges, including high misdiagnosis rate, difficulty in choosing between surgical and non-surgical treatment options, lack of standardized surgical protocols, interference from intralesional bone cement during procedures, inadequate stability of internal fixation in osteoporotic bone, and suboptimal compliance of anti-osteoporotic therapy. Establishing a standardized diagnostic and therapeutic framework is urgently needed. To standardize the management process and improve outcomes for vertebral refractures after PVA in elderly OTLCF patients, Spinal Trauma Group of the Orthopedic Branch of Chinese Medical Doctor Association organized experts in the field to develop Guideline for the diagnosis and treatment of vertebral refracture after percutaneous vertebral augmentation in elderly patients with osteoporotic thoracolumbar compression fractures ( version 2025), based on current literature and clinical experience, and adhering to principles of scientific rigor and clinical applicability. A total of 11 recommendations were proposed, encompassing diagnosis, treatment, and rehabilitation of vertebral refracture after PVA in elderly patients with OTLCF, aiming to provide a foundation for a standardized management.
9.Reliability and validity analysis of different measurement methods for quantifying glenoid bone defect proportion in bony Bankart lesions of the shoulder joint under 30° arthroscopy
Yiqi YANG ; Songyan LI ; Guangyuan DU ; Jingyi LI ; Jie LUO ; Huachen LIU ; Youzhi CAI ; Bin WANG
Chinese Journal of Trauma 2025;41(11):1077-1085
Objective:To investigate the reliability and validity of different measurement methods under 30° arthroscopy for quantifying the proportion of glenoid bone defect in bony Bankart lesions of the shoulder joint and validate its preliminary application effect.Methods:Eight intact shoulder glenoid specimens were selected, with no existing defects or deformities, from donors of 4 females and 4 males, with their age at death of 43-67 years [(54.4±8.0)years]. Bone defects of 12.5% and 25% were created in the glenoid at 0° and 45° relative to the longitudinal axis, with two specimens per defect category. The defect proportion in each specimen was quantified using direct measurement and CT-based digital reconstruction and these values served as reference standards for subsequent statistical analysis. Using a combined approach of arthroscopic simulation equipment and cadaveric study, five investigators performed simulated examinations through the standard posterior portal (2 cm medial and 1.5 cm inferior to the posterolateral acromial corner) and the modified posteroinferior portal (2 cm medial and 3 cm inferior to the posterolateral acromial corner) separately. Under 30° arthroscopy, the glenoid bone loss percentage was measured using the bare spot method and secant chord method. The reliability was analyzed for these measurements. Furthermore, using direct physical measurements and CT-based three-dimensional reconstruction data from the same specimens as reference standards, the comprehensive validity of four measurement methods was evaluated (standard posterior portal-bare spot method, standard posterior portal-secant chord method, modified posteroinferior portal-bare spot method, and modified posteroinferior portal-secant chord method). The independent validity of each method was assessed according to bone defect morphology classification to determine differences in measurement accuracy across defect types. In an arthroscopic procedure for a patient with Bigliani type IIIB bony Bankart lesion, the standard posterior portal-secant chord method was applied to quantify the proportion of glenoid bone defects.Results:The mean reference values from direct measurement and CT measurement of glenoid bone defect proportion in eight bony Bankart lesion specimens were 12.71%/12.37%, 13.17%/13.10%, 25.71%/24.9%, 26.6%/26.95%, 13.41%/13.10%, 12.90%/12.59%, 26.42%/25.94%, and 26.73%/27.06%, respectively. Measurements obtained by the five investigators showed intraclass correlation coefficients (ICCs) all greater than 0.90, indicating excellent interobserver agreement. In the validity analysis, the standard posterior portal-secant chord method demonstrated the highest overall validity. Using direct measurement and CT-based measurement as reference standards, the overall validity was (0.90±0.38)% and (1.07±0.53)% for the standard posterior portal-bare spot method, (1.33±0.40)% and (1.51±0.54)% for the modified posteroinferior portal-bare spot method, and (0.53±0.17)% and (0.70±0.38)% ( P<0.05) for the modified posteroinferior portal-secant chord method. In contrast, the standard posterior portal-secant chord method showed an overall validity of (0.10±0.10)% and (0.28±0.39)% ( P>0.05). In subsequent independent validity analyses, the standard posterior portal-secant chord method also demonstrated superior validity across all bone defect subtypes over the other three methods. In a patient with a Bigliani type IIIB bony Bankart lesion, we used the standard posterior portal-secant chord method to quantify the glenoid bone loss in 2 minutes, revealing a defect proportion of 26.6%. An arthroscopic autologous iliac bone graft procedure with single-tunnel elastic fixation guided by this measurement achieved favorable outcomes, with stable reduction, secure internal fixation and favorable recovery of shoulder function at 2 months postoperatively. Conclusion:For various types of bony Bankart lesions, the 30° arthroscopic standard posterior portal-secant chord method provides the most accurate quantification of glenoid bone loss and its preliminary clinical application yields satisfactory results.
10.Novel Structural Features of Isoflavone Synthase from Medicago truncatula Shed Light on Its Unique Enzymatic Mechanism
Chao SHI ; Zhao-Yang YE ; Fei XU ; Xiang-Ning DU ; Zhang-Xin CHEN ; Ming-Yue GU ; Jie DENG ; Wei WANG ; Liang-Yu LIU ; Mei-Ying WANG ; Xiao-Dong SU ; He-Li LIU ; Ming-Ying SHANG ; Li-Xin HUANG ; Zhen-Zhan CHANG
Chinese Journal of Biochemistry and Molecular Biology 2025;41(8):1204-1213,中插1-中插6
Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 ? by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Ⅰa-loop-helix Ⅰβ motif which cor-responds to helix Ⅰ of other P450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,the γ-domain.The structure reveals a homodimer in which the γ-domain of one molecule interacts with the β-domain of another.The plane of heme group makes an angle of ap-proximately 40° with the helix Ⅰa-loop-helix Ⅰβ motif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recogni-tion.Phe-301,Ser-303 and Gly-305 from the helix Ⅰa-loop-helix Ⅰβ motif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.

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