1.The Regulatory Effects and Mechanisms of Piezo1 Channel on Chondrocytes and Bone Metabolic Dysregulation in Osteoarthritis
Yan LI ; Tao LIU ; Yu-Biao GU ; Hui-Qing TIAN ; Lei ZHANG ; Bi-Hui BAI ; Zhi-Jun HE ; Wen CHEN ; Jin-Peng LI ; Fei LI
Progress in Biochemistry and Biophysics 2026;53(3):564-576
Osteoarthritis (OA), a highly prevalent degenerative joint disease worldwide, is defined by articular cartilage degradation, abnormal bone remodeling, and persistent chronic inflammation. It severely compromises patients’ quality of life, and currently, there is no radical cure. Abnormal mechanical stress is widely regarded as a core driver of OA pathogenesis, and the exploration of mechanical signal perception and transduction mechanisms has become crucial for deciphering OA’s pathophysiological processes. Piezo1, a key mechanosensitive cation channel belonging to the Piezo protein family, has recently gained significant attention due to its pivotal role in mediating cellular responses to mechanical stimuli in joint tissues. This review systematically examines Piezo1’s expression patterns, regulatory mechanisms, and pathological functions in OA, with a particular focus on its dual roles in modulating chondrocyte homeostasis and bone metabolism disorders, while also delving into the underlying molecular signaling pathways and potential therapeutic implications. Piezo1, consisting of approximately 2 500 amino acids and forming a unique trimeric propeller-like structure, is widely expressed in chondrocytes, osteocytes, mesenchymal stem cells, and synovial cells. It exhibits permeability to cations such as Ca2+, K+, and Na+, and directly responds to membrane tension changes induced by mechanical stimuli like fluid shear stress and mechanical overload. In OA patients and animal models, Piezo1 expression is significantly upregulated, especially in cartilage regions subjected to abnormal mechanical stress (e.g., human temporomandibular joint cartilage). This overexpression is closely associated with aggravated cartilage degeneration, increased chondrocyte apoptosis, accelerated cellular senescence, and intensified inflammatory responses. Mechanical overload and pro-inflammatory cytokines (e.g., IL-1β) are key inducers of Piezo1 upregulation: IL-1β activates the PI3K/AKT/mTOR signaling pathway to enhance Piezo1 expression, forming a pathogenic positive feedback loop that inhibits chondrocyte autophagy, promotes apoptosis, and further accelerates joint degeneration. Mechanistically, Piezo1 mediates OA progression through multiple interconnected pathways. When activated by mechanical stress, Piezo1 triggers excessive Ca2+ influx, leading to endoplasmic reticulum stress (ERS) and mitochondrial dysfunction, which directly induce chondrocyte apoptosis. This process involves the activation of downstream signaling cascades such as cGAS-STING and YAP-MMP13/ADAMTS5. YAP, a transcriptional regulator, upregulates the expression of matrix metalloproteinase 13 (MMP13) and aggrecanase (ADAMTS5), thereby accelerating cartilage matrix degradation. Additionally, Piezo1-driven Ca2+ overload promotes the accumulation of reactive oxygen species (ROS) and upregulates senescence markers (p16 and p21), accelerating chondrocyte senescence via the p38MAPK and NF-κB pathways. Senescent chondrocytes secrete senescence-associated secretory phenotype (SASP) factors (e.g., IL-6, IL-1β), further amplifying joint inflammation. In terms of bone metabolism, Piezo1 maintains joint homeostasis by promoting the differentiation of fibrocartilage stem cells into chondrocytes and balancing bone formation and resorption through regulating the FoxC1/YAP axis and RANKL/OPG ratio. Therapeutically, targeting Piezo1 shows promising potential. Preclinical studies have demonstrated that Piezo1 inhibitors (e.g., GsMTx4) can reduce joint damage and alleviate pain in OA mice. Simultaneously, siRNA-mediated co-silencing of Piezo1 and TRPV4 (another mechanosensitive channel) decreases intracellular Ca2+ concentration, inhibits chondrocyte apoptosis, and promotes cartilage repair. Conditional knockout of Piezo1 using Gdf5-Cre transgenic mice alleviates cartilage degeneration in post-traumatic OA models by downregulating MMP13 and ADAMTS5 expression. Despite existing challenges, such as off-target effects of inhibitors, inefficient local drug delivery, and interindividual genetic variability, strategies like developing selective Piezo1 antagonists, optimizing targeted nanocarriers, and combining Piezo1-targeted therapy with physical therapy provide viable avenues for clinical translation. The authors propose that Piezo1 serves as a critical therapeutic target for OA, and future research should focus on deciphering its context-dependent regulatory networks, developing tissue-specific intervention strategies, and validating their efficacy and safety in clinical trials to address the unmet medical needs of OA patients.
2.Evaluation of CARIFS Score and Negative Antigen Conversion Rate of Qingxuan Daozhi Formula in Treatment of Influenza in Children (Heat Accumulation in Lung and Stomach Syndrome):A Multi-center Randomized Controlled Clinical Study
Jing WANG ; Liqun WU ; Tiegang LIU ; Yongning CAO ; Jing QIU ; Jing LI ; Huaqing TAN ; Ying ZHANG ; Xulei GOU ; Jia WANG ; Jing LI ; Haipeng CHEN ; Xueying QIN ; Yuanshuo TIAN ; Yang WANG ; Chen BAI ; Zhendong WANG ; Qianqian LI ; He YU ; Xueyan MA ; Fei DONG ; Lin JIANG ; Yingqi XU ; Jianping LIU ; Xiaohong GU
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(13):188-196
ObjectiveThis paper aims to observe the syndrome improvement and negative antigen conversion rate of Qingxuan Daozhi formula in the treatment of influenza in children (heat accumulation in the lung and stomach syndrome). MethodsThrough a multi-center randomized controlled methodology design,confirmed influenza cases were collected from October 2022 to April 2023 in the pediatrics department of eight hospitals,such as Dongfang Hospital of Beijing University of Chinese Medicine. A total of 180 children with influenza and heat accumulation in the lung and stomach syndrome conforming to the standard were recruited through the clinic. The sick children meeting the inclusion criteria were randomly divided into groups by a block-randomized method. The children in the experimental group were treated with Qingxuan Daozhi formula for five days,and those in the control group were treated with Oseltamivir Phosphate Granules for five days. The primary efficacy indicator was the negative conversion rate of influenza antigen detection. Secondary efficacy indicators were the Canadian acute respiratory illness and flu scale (CARIFS) and the incidence of complications,severe cases, and critical cases. Follow-up observation was conducted on the day of enrollment,48 hours after medication,72 hours after medication, and (6+1) d after medication. ResultsOne hundred and eighty participants were randomly assigned to the experimental group (90 cases) or the control group (90 cases). All participants were followed up during the study. Comparison of influenza antigen detection results in the primary efficacy indicators showed that the average time of negative influenza antigen conversion in the experimental group was (5.29±1.25) d,and that in the control group was (5.40±1.68) d,without a statistically significant difference. After five days of intervention,52 cases in the experimental group and 51 cases in the control group converted to negative,without a statistically significant difference. CARIFS score results in the secondary efficacy indicators showed that during 72 hours after intervention,there were statistically significant differences between the experimental group and the control group in three dimensions, including headache,muscle soreness, and the need for extra care (P<0.05). On the (6+1) days after the intervention,the differences in both the experimental group and the control group were statistically significant in 10 dimensions, including sore throat,bad sleep,uncomfortable feeling,poor spirit and fatigue,crying more than usual,the need for extra care,symptom,function,influence on parents,and total score (P<0.05). The comparison results within the group in the dimensional scores of symptom, function, and influence on parents,as well as the CARIFS total score showed that with the delay of follow-up time,scores of both groups decreased significantly,with a statistically significant difference (P<0.01). Inter-group comparison results showed that the mean score of the experimental group was higher than that of the control group at the time of enrollment. With the progress of intervention,the score of the experimental group was significantly decreased compared with that of the control group. At the end of follow-up,the mean score of the experimental group was lower than that of the control group,with no statistically significant difference. In terms of the incidence of complications,severe cases, and critical cases, there were no complications,severe cases, and critical cases in the two groups,without a statistically significant difference. ConclusionThe symptom improvement effect and negative antigen conversion rate of Qingxuan Daozhi formula in the treatment of influenza in children (heat accumulation in the lung and stomach syndrome) are not inferior to Oseltamivir Phosphate granules, and children's acceptance is better. It can be more widely used in clinical treatment of influenza in children (heat accumulation in the lung and stomach syndrome).
3.Engineered Bacteriophages for The Treatment of Multidrug-resistant Bacterial Infections
Yu-Ying CHEN ; Chun-Mei HUANG ; Jin-Zhi PAN ; De-Liang LIU ; Yang ZHOU ; Gui-Qin DAI ; Peng-Fei ZHAO ; Hong-Zhou LU ; Ming-Bin ZHENG
Progress in Biochemistry and Biophysics 2026;53(6):1581-1596
Multidrug-resistant (MDR) bacterial infections have emerged as a serious challenge of global public health crisis. The overuse and misuse of conventional antibiotics have dramatically accelerated the emergence, evolution and worldwide spread of drug-resistant bacterial strains, necessitating urgent exploration of novel antibacterial strategies. Bacteriophages serve as natural bacterial predators offering distinct advantages including high host specificity, autonomous self-replication capabilities and cost-effective large-scale production. However, wild-type phages present significant clinical limitations due to their narrow host ranges, susceptibility to rapid immune clearance and poor penetration of bacterial biofilms, which severely restrict their therapeutic applications. The convergence of synthetic biology, nanotechnology and advanced gene editing technologies has accelerated the development of engineered bacteriophage platforms, providing programmable, scalable and clinically translatable pathways to overcome these inherent biological constraints. Here, we systematically delineate four fundamental strategies for engineered bacteriophage development. Chemical modification utilizes reactive functional groups such as amino, carboxyl and thiol moieties on capsid proteins through esterification, amidation or click chemistry reactions to achieve precise drug conjugation and surface functionalization. In vivo editing encompasses ultraviolet or chemical mutagenesis for random mutation induction, homologous recombination for targeted genetic alterations, recombineering methodologies including electroporation-mediated bacteriophage recombination engineering, and CRISPR-Cas systems for precise genome editing to enable exact genetic reconstruction and host range reprogramming. In vitro synthesis leverages genome engineering platforms where intact phage genomes are transferred into yeast or host bacteria to facilitate highly efficient homologous recombination, enabling large DNA fragment assembly and cross-gene host range expansion without bacterial toxicity constraints. Directed evolution combines artificial selection through mutation library screening with rational design approaches involving chimeric receptor binding protein construction or site-specific mutagenesis, effectively balancing the discovery of unknown adaptive pathways with targeted host specificity modification. Moreover, we comprehensively discuss therapeutic applications across diverse clinical scenarios. Engineered bacteriophage effectively disrupt bacterial biofilms through sophisticated functionalized delivery platforms including nanozyme-conjugated phages, phage-liposome nanoconjugates and bio-responsive hydrogels, demonstrating significantly enhanced bactericidal efficiency compared to unmodified free phages. These bioengineered vectors attenuate bacterial virulence and resensitize pathogens to antibiotics by delivering CRISPR-Cas systems or base editors to disrupt critical virulence factors such as pili, capsule synthesis machineries and quorum sensing systems, or by inactivating antibiotic resistance determinants including beta-lactamase genes. As an intelligent nanomedicine delivery platform, engineered bacteriophage enable precise pathogen elimination an through photocatalytic reactive oxygen species generation, immunomodulatory interventions, or controlled release of antibacterial drugs. Furthermore, oral administration of engineered bacteriophage facilitates microbiota modulation, which selectively eliminate intestinal pathogens while preserve beneficial commensal microbiota, thereby restoring microbial community balance and preventing complications associated with dysbiosis. Finally, we critically analyze persistent challenges including host strain matching complexity, evolution of bacterial resistance mechanisms, pharmacokinetic optimization requirements, optimal administration route selection, large-scale production quality control standards and clinical dosing determination protocols. Through multidisciplinary integration of synthetic biology, infectious disease medicine and immunology, future translational medicine studies of bacteriophage should establish comprehensive technical platforms encompassing rapid phage screening, intelligent rational design, rigorous in vivo evaluation and standardized clinical validation processes, ultimately advancing engineered bacteriophage from laboratory innovations to clinically approved therapeutics for effectively combating MDR bacterial infections.
4.Serotyping,virulence factors and drug resistance analysis of Pasteurella multocida of porcine origin of Zhejiang Province
Yizhen XU ; Xiufang YUAN ; Lihua XU ; Bin YU ; Fei SU ; Shiyi YE ; Hongchao SUN ; Yijie CHEN ; Qiaodan CHEN ; Hui ZHANG ; Junxing LI
Chinese Journal of Veterinary Science 2025;45(7):1378-1387
The aim of this paper was to investigate the serotypes,virulence factors and drug resist-ance of clinical isolates of Pasteurella rnultocida of porcine origin in recent years.Morphological screening and polymerase chain reaction(PCR)were used to isolate and identify 119 isolates from nasal swabs and lung tissue samples sent from swine farms in Zhejiang Province from 2010 to 2024.The isolates of Pasteurella multocida were subjected to capsular polysaccharide serotyping,lipopolysaccharide serotyping,virulence factor detection and drug resistance analysis by PCR and Kirby-Bauer disc agar diffusion method(K-B).The results showed that there were 64 strains(53.7%)of A-type,54 strains(45.3%)of D-type and 1 strain(0.9%)of F-type among the capsu-lar polysaccharide serotypes,and 10 strains(8.4%)of L1-type,20 strains(16.8%)of L3-type,86 strains(72.2%)of L6-type,and 3 strains(2.6%)of undetermined type among the lipopolysaccha-ride serotypes.The amplification results of 10 virulence genes showed that the detection rate of virulence genes hgbA,higbB and fimA was over 86.0%,the detection rate of toxA was 8.4%,while the virulence gene tbpA was not detected.There were also differences in the distribution vir-ulence genes in different capsular polysaccharide serotypes.Virulence factor pfhA was detected in type A and F but not in type D.The detection rate of adhesin gene tadD in serotype A(92.2%)was significantly higher than that of type D(9.3%),and,on the contrary,the detection rate of ad-hesin gene hsf-l in serotype D(90.7%)was significantly higher than that of type A(20.3%).Drug resistance analysis revealed that Pasteurella multocida showed high susceptibility to antimi-crobial drugs such as amoxicillin,ampicillin,cephalosporins,doxycycline,fosfenicol and ciprofloxa-cin,and showed strong resistance to antimicrobial drugs such as lincomycin,cotrimoxazole,genta-micin and amikacin,and there were 54 multi-drug resistant strains(78.3%).In summary,capsular polysaccharide serotypes were dominated by type A and D,lipopolysaccharide serotypes were dom-inated by L6,the distribution of some virulence genes varied greatly among different serotypes,and the proportion of multi-resistant strains was high,which provide reference for the prevention and control of this disease.
5.Typical failure treatment of large-aperture 16-slice spiral Siemens SOMATOM Sensation Open CT
Yu-kun ZHU ; Shi-dong CHENG ; Ming YANG ; Fei WENG ; Jing TIAN ; Chen LIANG
Chinese Medical Equipment Journal 2025;46(11):112-114
Three typical failures of large-aperture 16-slice spiral Siemens SOMATOM Sensation Open CT were introduced in terms of phenomenon,cause and treatment method.References were provided for medical engineers to treat similar failures.
6.Resveratrol attenuates hepatic inflammation and oxidative stress in rheumatoid arthritis via Nrf2/Keap1 pathway
Xue-fei FAN ; Jian ZHOU ; Su-huan CHEN ; Meng-yan ZHANG ; Hao-miao LIU ; Rui SU ; Guang-yi CHEN ; Yu-bao SHAO ; Tao YAO ; Xiao-yu CHEN
Chinese Pharmacological Bulletin 2025;41(5):861-867
Aim To explore the therapeutic effects of resveratrol(Res)on hepatic inflammation and oxida-tive stress in rheumatoid arthritis(RA),and to eluci-date the relationship of the regulatory mechanism of the Nrf2/Keap1 signaling pathway in it.Methods A mouse model of arthritis was induced using chicken type Ⅱ collagen in combination with complete Freund's adjuvant,and Res was administered by tube feeding for treatment.Serum liver function indices and levels of hepatic inflammation and oxidative stress were detected in mice.An in vitro cellular model of hepatic inflam-mation and oxidative stress was established by treating mouse primary hepatocytes(MPHs)with TNF-α(5μg·L-1),cell proliferation inhibition was detected by CCK-8,and inflammation and oxidative stress-relat-ed indices were detected by protein blotting.The in-trinsic mechanisms by which Res attenuated hepatic in-flammation and oxidative stress in rheumatoid arthritis were explored by treating MPHs with Nrf2 inhibitor and Keap1 overexpression plasmid.Results Res signifi-cantly reduced the levels of inflammation and oxidative stress in hepatic tissues of collagen-induced arthritis mice as well as TNF-α-treated MPHs,and activated the Nrf2/Keap1 signaling pathway.Inflammation and oxidative stress levels in MPHs were exacerbated by the use of Nrf2 inhibitors and Keap1 overexpression,which promoted apoptosis.Conclusion Res attenuates he-patic inflammation and oxidative stress in rheumatoid arthritis via the Nrf2/Keap1 pathway.
7.Analysis of learning curve of TiRobot-assisted lumbar pedicle screw fixation based on the cumulative sum test
Yuquan LIU ; Xiang LI ; Qi FEI ; Kuo CHEN ; Weiyang ZUO ; Bin ZHU ; Guoqiang ZHANG ; Lingjia YU ; Xuehu XIE ; Ning LIU ; Haining TAN ; Hai MENG ; Tianqi FAN ; Yong YANG
Chinese Journal of Postgraduates of Medicine 2025;48(1):10-17
Objective:To analyze the learning curve of TiRobot-assisted lumbar pedicle screw fixation (LPSF) by cumulative sum (CUSUM) test method.Methods:The clinical data of 50 patients who underwent TiRobot-assisted LPSF from January 2020 to December 2022 in Beijing Friendship Hospital, Capital Medical University were retrospectively analyzed. CUSUM analysis and learning curve fitting were performed with robot usage time as the main indicator with the time for each step refined (robot registration time, path planning time and guide wire placement time), to select the best learning curve fitting model with the R2 value closest to 1. Using the turning point of the learning curve as the boundary, the learning curve was divided into two stages as learning stage and maturity stage, and then the observation indexes were compared between the two stages. Results:All 50 patients successfully completed the surgery without perioperative complications, with a total of 244 pedicle screws implanted. The total robot usage time and robot registration time showed a gradually decreasing trend with the increase of case number, and the learning curves were successfully fitted and reached their peaks at the seventeenth and thirteenth cases respectively. The entire learning process was divided into learning stage (17 cases) and maturity stage (33 cases) based on the turning point of the learning curve of total robot usage time. The path planning time and guide wire placement time did not show significant changes with the increase in the case number. The total robot usage time, robot registration time and the intraoperative blood loss in the learning stage were significantly higher than those in the maturity stage: (35.35 ± 1.58) min vs. (30.61 ± 0.43) min, (20.83 ± 1.56) min vs. (14.94 ± 0.29) min and 400 (150, 500) ml vs. 200 (110, 300) ml, the guide wire placement time of per screw was significantly lower than that in the maturity stage: 2.00 (1.83, 2.34) min/screw vs. 2.33 (2.13, 2.69) min/screw, and there were statistical differences ( P<0.05 or <0.01). There were no statistical difference in the path planning time, path planning time of per screw, guide wire placement time and the accuracy of screw placement between two stages ( P>0.05). Conclusions:TiRobot-assisted LPSF is a new technology with safety and effectiveness, and it has a relatively short learning curve. To achieve technological maturity, at least 17 surgeries are required with accumulated experience, and the robot registration is the main step of the learning process. After reaching maturity stage, the robot usage time is significantly shortened and intraoperative trauma is significantly reduced while the relatively high screw placement accuracy is ensured.
8.Study on the Effect of Cuproptosis on Diabetic Cardiomyopathy Based on"Qi Collateral Theory"
Yuting LIN ; Kun YU ; Fei CHEN ; Bin LI ; Qiufang OUYANG ; Jinjian GUO
World Science and Technology-Modernization of Traditional Chinese Medicine 2025;27(8):2176-2182
Diabetic cardiomyopathy(DCM)is one of the complications of diabetes.The onset of DCM is hidden and easy to be ignored.Myocardial injury is serious in the later stage and the prognosis is poor.At present,symptomatic treatment is the main clinical treatment.Cuproptosis is a novel cell death mode caused by imbalanced copper ion concentration in the body,leading to mitochondrial metabolic abnormalities,which is one of the important mechanisms of DCM.Targeted cuproptosis pathway therapy for DCM is currently a focus and hotspot of research.The"Qi Luo Theory"is one of the disciplinary branches of the theory of collateral diseases,which mainly operates the meridian Qi system.The syndrome and treatment system of collateral diseases cardiovascular diseases have important guiding significance for the treatment of DCM.Traditional Chinese medicine believes that deficiency and stagnation of Qi that in the collaterals are the root causes of DCM,with stasis and toxin obstructing collaterals and damage to the heart collaterals being the core of the disease.The ultimate outcome is the deficiency and decline of Qi,Blood,Yin,and Yang in the heart.The"Qi Luo Theory"and cuproptosis have similarities in physiological functions and pathological processes,and cuproptosis can be said to be one of the microscopic manifestations of the"Qi Luo theory".Based on this,the staged treatment principle of tonifying deficiency and promoting stagnation as the norm,attacking and supplementing simultaneously as the principle,and strengthening the body and consolidating the core has been proposed,in order to provide theoretical reference for the clinical treatment of DCM.
9.Clinicopathological analysis of 12 cases of CD23-positive diffuse large B-cell lym-phoma
Susu ZHAO ; Fei KE ; Hui YU ; Xiaoli CHEN ; Yaohui WANG ; Shuangshuang WANG ; Yifen ZHANG
Chinese Journal of Clinical and Experimental Pathology 2025;41(8):1011-1016
Purpose To investigate the clinicopathological features and possible tumor-associated immune micro-environment in CD23-positive diffuse large B-cell lymphoma(DLBCL).Methods The clinicopathological data of 12 cases of CD23-positive DLBCL patients were analyzed retrospectively.The clinical and pathological features were ana-lyzed,and the clinical correlation and tumor-associated immune invasion were studied.Results CD23-positive DL-BCL accounted for 9.45%of all DLBCL.There were 6 males and 6 females.The mean age of onset was 64.83 years old.Four DLBCL cases occurred in lymph nodes and 8 cases occurred outside lymph nodes.Nine DLBCL cases were in advanced stage(Ⅲ-Ⅳ)and 3 cases DLBCL were in early stage(Ⅰ-Ⅱ).Among the patients,3 cases were untreated and lost to follow-up.One case deteriorated and died after operation.Two cases died,1 case progressed and 5 cases partially recovered after chemotherapy.Microscopically,the tumor cells were diffusely infiltrated and destroyed the nor-mal tissue structure.The tumor cells were observed to be centroblastic,immunoblastic and anaplastic large cells.No blastoid transformation and plasmacytoid differentiation were observed in morphology.According to Hans algorithm,11 cases were non-GCB phenotype except 1 case was GCB phenotype.Bioinformatics studies revealed that CD23 expres-sion was correlated with regulatory T cells,NK cells,plasma-like dendritic cells and neutrophils.Conclusion CD23-positive DLBCL patients are mainly middle-aged and elderly,and most of them occur outside lymph nodes and in ad-vanced stage(Ⅲ-Ⅳ).Follow-up results show that their prognosis is poor.Morphologically,there is no significant difference between DLBCL and conventional DLBCL.The Hans classification suggests that most cases originated from activated B cells.CD23 expression may play a role in the immune microenvironment of DLBCL.
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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