1.Sclera Vessel Segmentation Based on Fusion Filtering and Reflection Suppression
Ming-Xuan FAN ; Zong-Qing MA ; Chu-Xiang GAO ; Yi-Xuan SHI ; Zi-Hang ZHANG ; Zhe-Xuan JIA ; Fan FAN ; Guo-Liang HUANG ; Jiang ZHU
Progress in Biochemistry and Biophysics 2026;53(5):1195-1206
ObjectiveIn traditional Chinese medicine (TCM), the foundational doctrine that the eyes reflect the essence of the internal viscera establishes ocular observation as a cornerstone of diagnostic practice. Specifically, the morphological characteristics and coloration variations of the scleral microvasculature serve as critical clinical indicators for assessing the dynamic balance of Qi and Blood, as well as the pathological status of internal organs. Historically, however, TCM eye diagnosis has relied predominantly on the subjective clinical experience and visual acuity of individual practitioners, leading to inherent challenges in standardization and reproducibility. While automated computer-aided diagnostic systems offer a promising solution, existing vessel segmentation algorithms encounter significant domain-specific bottlenecks when applied to scleral imagery. These challenges primarily stem from the highly reflective and moist nature of the ocular surface, which generates severe reflective interference. Furthermore, the inherent low contrast of fine capillary networks against complex background textures, compounded by non-uniform illumination, frequently results in high false-positive rates, misdetections, and severe vessel fragmentation. To address these critical limitations and advance the objective quantification of TCM diagnostics, this paper proposes a novel, highly robust sclera vessel segmentation framework that innovatively integrates Frangi-Sato dual-filter adaptive enhancement with pixel-level reflection detection. MethodsThe proposed methodology systematically addresses the segmentation pipeline through three synergistic stages. First, to overcome the structural limitations of single-filter approaches, a multi-scale weighted fusion strategy is meticulously designed to harness the complementary extraction capabilities of both Frangi and Sato filters. This adaptive enhancement optimally balances the preservation of main vessel trunk continuity with the heightened sensitivity required for delineating delicate, low-contrast peripheral capillaries. Second, to tackle the persistent issue of reflective highlights, a sophisticated multi-feature synergistic reflection detection module is introduced. By jointly analyzing local information entropy, gradient field variations, and intensity statistical distributions, this module achieves precise, pixel-level identification and elimination of reflective artifacts without compromising the underlying vascular structures. Finally, a dual-level adaptive thresholding strategy, featuring an innovative “core protection” mechanism, is implemented. This critical step effectively suppresses complex background noise while rigorously preserving the structural and topological integrity of the intricate vessel network, preventing the structural breaks often seen in conventional binarization methods. ResultsThe efficacy of the proposed framework was rigorously evaluated using both self-constructed clinical datasets specifically acquired for TCM research and standardized public datasets. Extensive experimental results demonstrate that the proposed method consistently outperforms state-of-the-art traditional approaches and contemporary deep learning models. Specifically, the proposed method achieves a Dice similarity coefficient of approximately 0.71 on the private clinical dataset, and secures the best performance across the majority of quantitative metrics on both datasets. Notably, the framework exhibits exceptional robustness and generalization capabilities in highly challenging scenarios characterized by intense reflective interference, low signal-to-noise ratios, and cross-domain image variations. ConclusionThis study successfully realizes the high-integrity, automated segmentation of scleral vessel networks under complex clinical imaging conditions. By overcoming the fundamental algorithmic challenges of reflection interference and micro-vessel loss, the proposed methodology provides potential support for the digitization, objective standardization, and intelligent advancement of modern TCM eye diagnosis systems.
2.Sclera Vessel Segmentation Based on Fusion Filtering and Reflection Suppression
Ming-Xuan FAN ; Zong-Qing MA ; Chu-Xiang GAO ; Yi-Xuan SHI ; Zi-Hang ZHANG ; Zhe-Xuan JIA ; Fan FAN ; Guo-Liang HUANG ; Jiang ZHU
Progress in Biochemistry and Biophysics 2026;53(5):1195-1206
ObjectiveIn traditional Chinese medicine (TCM), the foundational doctrine that the eyes reflect the essence of the internal viscera establishes ocular observation as a cornerstone of diagnostic practice. Specifically, the morphological characteristics and coloration variations of the scleral microvasculature serve as critical clinical indicators for assessing the dynamic balance of Qi and Blood, as well as the pathological status of internal organs. Historically, however, TCM eye diagnosis has relied predominantly on the subjective clinical experience and visual acuity of individual practitioners, leading to inherent challenges in standardization and reproducibility. While automated computer-aided diagnostic systems offer a promising solution, existing vessel segmentation algorithms encounter significant domain-specific bottlenecks when applied to scleral imagery. These challenges primarily stem from the highly reflective and moist nature of the ocular surface, which generates severe reflective interference. Furthermore, the inherent low contrast of fine capillary networks against complex background textures, compounded by non-uniform illumination, frequently results in high false-positive rates, misdetections, and severe vessel fragmentation. To address these critical limitations and advance the objective quantification of TCM diagnostics, this paper proposes a novel, highly robust sclera vessel segmentation framework that innovatively integrates Frangi-Sato dual-filter adaptive enhancement with pixel-level reflection detection. MethodsThe proposed methodology systematically addresses the segmentation pipeline through three synergistic stages. First, to overcome the structural limitations of single-filter approaches, a multi-scale weighted fusion strategy is meticulously designed to harness the complementary extraction capabilities of both Frangi and Sato filters. This adaptive enhancement optimally balances the preservation of main vessel trunk continuity with the heightened sensitivity required for delineating delicate, low-contrast peripheral capillaries. Second, to tackle the persistent issue of reflective highlights, a sophisticated multi-feature synergistic reflection detection module is introduced. By jointly analyzing local information entropy, gradient field variations, and intensity statistical distributions, this module achieves precise, pixel-level identification and elimination of reflective artifacts without compromising the underlying vascular structures. Finally, a dual-level adaptive thresholding strategy, featuring an innovative “core protection” mechanism, is implemented. This critical step effectively suppresses complex background noise while rigorously preserving the structural and topological integrity of the intricate vessel network, preventing the structural breaks often seen in conventional binarization methods. ResultsThe efficacy of the proposed framework was rigorously evaluated using both self-constructed clinical datasets specifically acquired for TCM research and standardized public datasets. Extensive experimental results demonstrate that the proposed method consistently outperforms state-of-the-art traditional approaches and contemporary deep learning models. Specifically, the proposed method achieves a Dice similarity coefficient of approximately 0.71 on the private clinical dataset, and secures the best performance across the majority of quantitative metrics on both datasets. Notably, the framework exhibits exceptional robustness and generalization capabilities in highly challenging scenarios characterized by intense reflective interference, low signal-to-noise ratios, and cross-domain image variations. ConclusionThis study successfully realizes the high-integrity, automated segmentation of scleral vessel networks under complex clinical imaging conditions. By overcoming the fundamental algorithmic challenges of reflection interference and micro-vessel loss, the proposed methodology provides potential support for the digitization, objective standardization, and intelligent advancement of modern TCM eye diagnosis systems.
3.Machine learning-assisted microfluidic approach for broad-spectrum liposome size control.
Yujie JIA ; Xiao LIANG ; Li ZHANG ; Jun ZHANG ; Hajra ZAFAR ; Shan HUANG ; Yi SHI ; Jian CHEN ; Qi SHEN
Journal of Pharmaceutical Analysis 2025;15(6):101221-101221
Liposomes serve as critical carriers for drugs and vaccines, with their biological effects influenced by their size. The microfluidic method, renowned for its precise control, reproducibility, and scalability, has been widely employed for liposome preparation. Although some studies have explored factors affecting liposomal size in microfluidic processes, most focus on small-sized liposomes, predominantly through experimental data analysis. However, the production of larger liposomes, which are equally significant, remains underexplored. In this work, we thoroughly investigate multiple variables influencing liposome size during microfluidic preparation and develop a machine learning (ML) model capable of accurately predicting liposomal size. Experimental validation was conducted using a staggered herringbone micromixer (SHM) chip. Our findings reveal that most investigated variables significantly influence liposomal size, often interrelating in complex ways. We evaluated the predictive performance of several widely-used ML algorithms, including ensemble methods, through cross-validation (CV) for both liposome size and polydispersity index (PDI). A standalone dataset was experimentally validated to assess the accuracy of the ML predictions, with results indicating that ensemble algorithms provided the most reliable predictions. Specifically, gradient boosting was selected for size prediction, while random forest was employed for PDI prediction. We successfully produced uniform large (600 nm) and small (100 nm) liposomes using the optimised experimental conditions derived from the ML models. In conclusion, this study presents a robust methodology that enables precise control over liposome size distribution, offering valuable insights for medicinal research applications.
4.Associations of Exposure to Typical Environmental Organic Pollutants with Cardiopulmonary Health and the Mediating Role of Oxidative Stress: A Randomized Crossover Study.
Ning GAO ; Bin WANG ; Ran ZHAO ; Han ZHANG ; Xiao Qian JIA ; Tian Xiang WU ; Meng Yuan REN ; Lu ZHAO ; Jia Zhang SHI ; Jing HUANG ; Shao Wei WU ; Guo Feng SHEN ; Bo PAN ; Ming Liang FANG
Biomedical and Environmental Sciences 2025;38(11):1388-1403
OBJECTIVE:
The study aim was to investigate the effects of exposure to multiple environmental organic pollutants on cardiopulmonary health with a focus on the potential mediating role of oxidative stress.
METHODS:
A repeated-measures randomized crossover study involving healthy college students in Beijing was conducted. Biological samples, including morning urine and venous blood, were collected to measure concentrations of 29 typical organic pollutants, including hydroxy polycyclic aromatic hydrocarbons (OH-PAHs), bisphenol A and its substitutes, phthalates and their metabolites, parabens, and five biomarkers of oxidative stress. Health assessments included blood pressure measurements and lung function indicators.
RESULTS:
Urinary concentrations of 2-hydroxyphenanthrene (2-OH-PHE) ( β = 4.35% [95% confidence interval ( CI): 0.85%, 7.97%]), 3-hydroxyphenanthrene ( β = 3.44% [95% CI: 0.19%, 6.79%]), and 4-hydroxyphenanthrene (4-OH-PHE) ( β = 5.78% [95% CI: 1.27%, 10.5%]) were significantly and positively associated with systolic blood pressure. Exposures to 1-hydroxypyrene (1-OH-PYR) ( β = 3.05% [95% CI: -4.66%, -1.41%]), 2-OH-PHE ( β = 2.68% [95% CI: -4%, -1.34%]), and 4-OH-PHE ( β = 3% [95% CI: -4.68%, -1.29%]) were negatively associated with the ratio of forced expiratory volume in the first second to forced vital capacity. These findings highlight the adverse effects of exposure to multiple pollutants on cardiopulmonary health. Biomarkers of oxidative stress, including 8-hydroxy-2'-deoxyguanosine and extracellular superoxide dismutase, mediated the effects of multiple OH-PAHs on blood pressure and lung function.
CONCLUSION
Exposure to multiple organic pollutants can adversely affect cardiopulmonary health. Oxidative stress is a key mediator of the effects of OH-PAHs on blood pressure and lung function.
Humans
;
Oxidative Stress/drug effects*
;
Male
;
Cross-Over Studies
;
Female
;
Young Adult
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Environmental Pollutants/toxicity*
;
Environmental Exposure/adverse effects*
;
Biomarkers/blood*
;
Adult
;
Blood Pressure/drug effects*
;
Polycyclic Aromatic Hydrocarbons/urine*
;
Beijing
5.The efficacy and safety of high-frequency irreversible electroporation for benign prostatic hyperplasia: a randomized controlled open-label multicenter trial
Liang DONG ; Zhen TONG ; Benkang SHI ; Qianyuan ZHUANG ; Yuanwei LI ; Min GONG ; Xiaoming XU ; Shengcai ZHOU ; Xulai TAO ; Xinxing DU ; Haifeng WANG ; Jian HUANG ; Wei XUE
Chinese Journal of Urology 2025;46(3):161-165
Objective:To investigate the efficacy and safety of high-frequency irreversible electroporation (H-FIRE) in treating benign prostatic hyperplasia (BPH).Methods:This randomized controlled open-label multicenter clinical trial enrolled patients from nine medical centers in China between August 2020 and July 2022. Inclusion criteria: age 50–80 years, International Prostate Symptom Score (IPSS) ≥12, maximum urinary flow rate (Q max) >5 ml/min and ≤15 ml/min. Exclusion criteria: prostate malignancy, contraindications to surgery or anesthesia. Patients were randomized 1∶1 into the H-FIRE group (experimental) or the control group (daily oral 0.2 mg tamsulosin hydrochloride sustained-release capsules). Primary outcomes included Q max, IPSS, prostate volume, and International Index of Erectile Function-5 (IIEF-5) scores, measured at baseline, 1 and 3 months post-treatment. Results:A total of 160 cases were included in this study, including 80 cases in the experimental group and 80 cases in the control group, 30 cases in Renji Hospital, 7 cases in Qilu Hospital of Shandong University, 8 cases in Tongji Hospital, 3 cases in Hunan Provincial Hospital, 13 cases in Shanghai Pudong Hospital, 29 cases in Hwa Mei Hospital, 18 cases in Yiyuan County People's Hospital, and 38 cases in Shanghai East Hospital, and 14 cases in Sun Yat-sen Memorial Hospital. At 3 months of post-treatment, Q max in the experimental group increased by a median of 7.50 (3.55, 14.50) ml/s from the baseline value, whereas in the control group it increased by a median of 1.70 (-1.40, 6.00) ml/s, and the difference between the two groups was statistically significant ( P < 0.01, U = 1 083); and at 3 months of post-treatment, IPSS in the experimental group decreased by a median of 12.00 (7.00, 17.00) points in the test group and 6.00 (2.00, 11.00) points in the control group, and the magnitude of improvement in IPSS scores in the test group was significantly higher than that in the control group ( P < 0.01, U = 1 248); at 3 months of post-treatment, the prostate volume decreased by a median of 12.16 (5.69, 18.27) ml in the experimental group and 0 (-3.94, 6.89) ml in the control group, suggesting that H-FIRE significantly reduced prostate gland volume ( P<0.01, U=1 111). The difference in elevated IIEF-5 scores from baseline at 3 months of treatment between the experimental and control groups was not statistically significant[0(-2.00, 1.00) points vs. 0(-2.00, 1.50) points; P=0.54, U=2 338]. There were no serious adverse events in the two groups. Conclusions:H-FIRE could significantly improve both subjective and objective symptoms of BPH with a low risk of severe complications.
6.Feasibility and exploration of optimal communication models for robot-assisted urological telesurgery: a multicenter, single-arm, retrospective study
Ye WANG ; Taoping SHI ; Sheng TAI ; Sunyi YE ; Yubai ZHANG ; Bingzhang QIAO ; Chenfeng WANG ; Gen CHENG ; Zhi LI ; Qing AI ; Qingbo HUANG ; Baojun WANG ; Qing YUAN ; Junnan XU ; Guojun LIU ; Yu CHEN ; Wuyi ZHAO ; Jianle MAO ; Shiwei LI ; Shuo WANG ; Dan XIA ; Wanhai XU ; Chaozhao LIANG ; Hongzhao LI ; Xin MA ; Xu ZHANG
Chinese Journal of Urology 2025;46(5):331-336
Objective:To evaluate the efficacy and feasibility of a domestically developed robotic surgical system based on fiber-optic dedicated line communication in cross-regional urological telesurgery.Methods:This was multicenter,single-arm,retrospective case series study. The data of patients who underwent urological telesurgeries using the telesurgical system between January 2023 and December 2024 were analyzed. The cohort included 59 patients from seven hospitals across China. Among the patients,47 were male(79.7%)and 12 were female(20.3%),with a median age of 63.0(56.0,68.0)years and a body mass index of(24.7 ± 3.0)kg/m 2. Surgical procedures included 32 radical prostatectomies,24 partial nephrectomies,one radical nephrectomy,one adrenalectomy,and one ureteral reconstruction. The perioperative indicators,pathological results and postoperative complications were analyzed. The network monitoring data were collected,and the perioperative data of patients,remote system monitoring data and costs were compared between the two communication modes of optical transport network(OTN)and cloud-connect network(CCN). Results:All 59 remote surgeries were successfully completed,with a mean operative time of(138.0 ± 54.0)minutes,median intraoperative blood loss of 50.0(30.0,100.0)ml and a postoperative hospital stay of 5.0(4.0,6.0)days. No cases required reoperation,Clavien-Dindo grade ≥3 complications,or readmission. The geographical distance between the primary and remote surgical sites ranged from 450 to 2 800 km. Network monitoring revealed increased bidirectional latency with distance increasing:the shortest latency time(Hefei-Hangzhou,450 km)was(16.59 ± 0.80)ms,while the longest(Harbin-Hangzhou,2 200 km)latency time was(53.31 ± 0.31)ms. Average frame loss per procedure was 0?1.27 frames. The results of subgroup analysis comparing OTN and CCN communication modes showed no significant differences in operative time[(130.7 ± 70.5)minutes vs.(142.1 ± 42.9)minutes, P = 0.442],postoperative hospitalization[6.0(4.0,8.0)d vs. 5.0(4.0,6.0)d, P = 0.581],or readmission rates(0 vs. 0). However,CCN demonstrated significant cost advantages with 500 RMB per operation vs. 3 000 RMB per operation for OTN. Conclusions:Urological telesurgery using fiber-optic communication is feasible. The CCN mode,with its cost-effectiveness,excellent usability,and multi-point interconnection flexibility,is currently the preferred communication model for telesurgical applications.
7.AHP Combined with Response Surface Method to Optimize the Simmering Process of Rhei Radix et Rhizoma and Correlation Analysis between Composition and Color
Huilian DAI ; Yu DING ; Ziyu LIANG ; Xinyuan LIU ; Wei HUANG ; Chanming LIU ; Yueqin ZHU ; Dianhua SHI ; Yanpeng DAI ; Lin LI
Journal of Nanjing University of Traditional Chinese Medicine 2025;41(5):652-660
OBJECTIVE To explore the optimal parameters of simmered Rhei Radix et Rhizoma and the correlation between the chroma values and the intrinsic composition of simmered Rhei Radix et Rhizoma decoction pieces powder.METHODS The single-factor-response surface method was used to investigate the simmering temperature,simmering time,paper dosage and plant ash dos-age,the response surface experiment was carried out on the basis of the single factor experiment,the appearance traits,total anthraqui-nones,free anthraquinones,leachables,sennoside A and B contents were taken as indicators,the analytic hierarchy process(AHP)was used to give weights to each index,and the process was optimized.The chroma values of raw and simmered products were deter-mined by electronic eye,the correlation and regression analysis were carried out by SPSS22.0 software,and the chroma-component re-gression equation was constructed.RESULTS The optimal process of simmering Rhei Radix et Rhizoma was 140 ℃,5 times of plant ash,2 layers of wet paper wrapped and being simmered for 2.5 h.CONCLUSION The simmering process of Rhei Radix et Rhizoma optimized by AHP combined with response surface method is reasonable and feasible,the color of decoction pieces has a significant correlation with the component content,and the regression equation constructed is reliable,which can predict the intrinsic component content of decoction pieces through chroma values.
8.Research advances in mitochondrial inflammation-mediated damage in central nervous system degenerative disorders
Shu-qin LI ; Sha-sha LIU ; Qian YAN ; Han-long WANG ; Yang SUN ; Yan-ting HUANG ; Hao-jie ZHANG ; Jin-ping LIANG ; Shi-feng CHU ; Yan-tao YANG ; Qi-di AI ; Nai-hong CHEN
Chinese Pharmacological Bulletin 2025;41(12):2218-2225
Central nervous system(CNS)degenerative disorders refer to a spectrum of pathological alterations triggered by struc-tural damage to cerebral neural tissues,clinically manifested as diverse neurological dysfunction syndromes,including multiple sclerosis(MS),neurodegenerative diseases(NDs),and ische-mic stroke.The hallmark pathological features of these disorders involve irreversible neuronal damage and decompensation of functional neural networks,ultimately leading to progressive neurological deficits.Notably,with the accelerating global popu-lation aging,the incidence of these diseases has surged signifi-cantly.According to WHO statistics,they now rank among the top three global causes of disability and mortality.Current re-search has confirmed that the pathogenesis of CNS degenerative disorders exhibits high heterogeneity,encompassing multifaceted pathophysiological processes such as genetic predisposition,oxi-dative stress,protein misfolding,and metabolic dysregulation.This intricate pathogenic network not only complicates clinical differential diagnosis but also poses substantial challenges to the development of precision therapeutic strategies.Importantly,re-cent studies have revealed that mitochondrial homeostasis disrup-tion-induced inflammatory cascades(termed mitochondrial in-flammation)play a pivotal regulatory role in neurodegenerative progression.Key molecular mechanisms include impaired mito-phagy,aberrant mitochondrial DNA(mtDNA)release and NL-RP3 inflammasome activation.This review systematically deci-phers the molecular regulatory network of mitochondrial inflam-mation,with a focus on its biological effects in critical pathologi-cal events such as blood-brain barrier disruption,microglial hy-peractivation and neuronal apoptosis.The overarching aim is to provide a theoretical foundation for developing innovative thera-peutic strategies targeting mitochondrial homeostasis restoration.
9.Effects of Poria cocos polysaccharides on improving mouse nonalcoholic fatty liver disease via regulation of Akt/mTOR/SREBP-1c signaling pathway
Shi-yao HUANG ; Liang KONG ; Jia-hua WANG ; Li-yan WANG ; Chao-wei SUN ; Xin-cheng LIU ; Yu-he DONG ; Li-yan GU
Chinese Traditional Patent Medicine 2025;47(1):58-65
AIM To investigate the improvement effects of Poria cocos polysaccharides(PCPs)on mouse nonalcoholic fatty liver disease(NAFLD).METHODS Forty-eight C57BL/6 mice were randomly divided into the blank group,the model group,the simvastatin group(4 mg/kg)and the high,medium and low dose PCPs groups(200,100 and 50 mg/kg),with 8 mice in each group.The NAFLD model was reproduced by 16 weeks feeding of high-fat and high-cholesterol diet,followed by 8 weeks administration of corresponding drug by gavage.The mice had their body mass and liver coefficient assessed;their levels of hepatic free fatty acid(FFA),and serum total cholesterol(TC),triglyceride(TG),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C),aspartate aminotransferase(AST),alanine aminotransferase(ALT),γ-glutamyltransferase(γ-GT)and malondialdehyde(MDA)detected;their hepatic pathological changes and lipid deposition observed using HE staining,NAFLD activity score(NAS)and oil red O staining;and their hepatic protein expressions of Akt,mTOR,p-Akt,p-mTOR and SREBP-1c detected by Western blot.RESULTS Compared with the blank group,the model group demonstrated all increased body weight,liver coefficient,hepatic FFA level,and serum TC,TG,LDL-C,AST,ALT,γ-GT,MDA,IL-1β and TNF-α.levels(P<0.05,P<0.01);decreased HDL-C level and activities of SOD and GSH-Px(P<0.05,P<0.01);more obvious hepatic pathological damage as revealed by increased NAS score(P<0.01)and increased lipid deposition area(P<0.01).Compared with the model group,the groups intervened with high or medium dose PCPs,or simvastatin displayed decreased body weight,liver coefficient,hepatic FFA level,and serum TC,TG,LDL-C,AST,ALT,γ-GT,MDA,IL-1β and TNF-α levels(P<0.05,P<0.01);increased HDL-C level and SOD,GSH-Px activities(P<0.05,P<0.01);decreased hepatic pathological damage as revealed by the decreased NAS score and lipid deposition area(P<0.05,P<0.01);and decreased hepatic protein expressions of p-Akt,p-mTOR and SREBP-1c protein(P<0.05)as well.CONCLUSION PCPs can improve mouse NAFLD,and its mechanism may lie in their function in reversing abnormal lipid metabolism via Akt/mTOR/SREBP-1c signaling pathway.
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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