RESUMEN
Expression of the receptor tyrosine kinase ephrin receptor A10 (EphA10), which is undetectable in most normal tissues except for the male testis, has been shown to correlate with tumor progression and poor prognosis in several malignancies, including triple-negative breast cancer (TNBC). Therefore, EphA10 could be a potential therapeutic target, likely with minimal adverse effects. However, no effective clinical drugs against EphA10 are currently available. Here, we report high expression levels of EphA10 in tumor regions of breast, lung, and ovarian cancers as well as in immunosuppressive myeloid cells in the tumor microenvironment. Furthermore, we developed anti-EphA10 monoclonal antibodies (mAbs) that specifically recognize cell surface EphA10, but not other EphA family isoforms, and target tumor regions precisely in vivo with no apparent accumulation in other organs. In syngeneic TNBC mouse models, we found that anti-EphA10 mAb clone #4 enhanced tumor regression, therapeutic response rate, and T cell-mediated antitumor immunity. Notably, the chimeric antigen receptor T cells derived from clone #4 significantly inhibited TNBC cell viability in vitro and tumor growth in vivo. Together, our findings suggest that targeting EphA10 via EphA10 mAbs and EphA10-specific chimeric antigen receptor-T cell therapy may represent a promising strategy for patients with EphA10-positive tumors.
Asunto(s)
Anticuerpos Monoclonales , Receptores Quiméricos de Antígenos , Receptores de la Familia Eph , Linfocitos T , Neoplasias de la Mama Triple Negativas , Animales , Anticuerpos Monoclonales/metabolismo , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Antineoplásicos Inmunológicos/uso terapéutico , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Humanos , Ratones , Receptores de la Familia Eph/inmunología , Linfocitos T/metabolismo , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
This retrospective study aims to explore whether the COVID-19 pandemic altered patient conditions and surgery outcomes by studying 213 pressure injury (PI) patients who underwent surgery during 2016 to 2019 (pre-COVID) and 2020 to 2021 (COVID) in Taiwan. We extracted patient demographics, surgical and blood test records, preoperative vital signs, and flap surgery outcomes. In total, 464 surgeries were performed, including 308 pre-COVID and 156 COVID. During the COVID period, there were more patients presenting with dementia, and it had significantly more patients with >12 000 white blood cells/µL (24.03% vs 15.59%, P = 0.029), higher C-reactive protein levels (7.13 ± 6.36 vs 5.58 ± 5.09 mg/dL, P = 0.014), pulse rates (86.67 ± 14.76 vs 81.26 ± 13.66 beats/min, P < 0.001), and respiratory rates (17.87 ± 1.98 vs 17.31 ± 2.39 breaths/min, P = 0.009) but lower haemoglobin levels (9.75 ± 2.02 vs 10.43 ± 1.67 mg/dL, P < 0.001) preoperatively. There were no between-group differences in flap surgery outcomes but had fewer flap surgeries during COVID-19. Thus, PI patient condition was generally poor during the COVID-19 pandemic because of reduced access to medical treatment; this problem may be resolved through holistic care during a future pandemic or pandemic-like situation.
Asunto(s)
COVID-19 , Úlcera por Presión , Humanos , COVID-19/epidemiología , Pandemias , Úlcera por Presión/etiología , Úlcera por Presión/cirugía , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND & AIMS: There are currently limited therapeutic options for hepatocellular carcinoma (HCC), particularly when it is diagnosed at advanced stages. Herein, we examined the pathophysiological role of ROS1 and assessed the utility of ROS1-targeted therapy for the treatment of HCC. METHODS: Recombinant ribonucleases (RNases) were purified, and the ligand-receptor relationship between RNase7 and ROS1 was validated in HCC cell lines by Duolink, immunofluorescence, and immunoprecipitation assays. Potential interacting residues between ROS1 and RNase7 were predicted using a protein-protein docking approach. The oncogenic function of RNase7 was analyzed by cell proliferation, migration and invasion assays, and a xenograft mouse model. The efficacy of anti-ROS1 inhibitor treatment was evaluated in patient-derived xenograft (PDX) and orthotopic models. Two independent patient cohorts were analyzed to evaluate the pathological relevance of RNase7/ROS1. RESULTS: RNase7 associated with ROS1's N3-P2 domain and promoted ROS1-mediated oncogenic transformation. Patients with HCC exhibited elevated plasma RNase7 levels compared with healthy individuals. High ROS1 and RNase7 expression were strongly associated with poor prognosis in patients with HCC. In both HCC PDX and orthotopic mouse models, ROS1 inhibitor treatment markedly suppressed RNase7-induced tumorigenesis, leading to decreased plasma RNase7 levels and tumor shrinkage in mice. CONCLUSIONS: RNase7 serves as a high-affinity ligand for ROS1. Plasma RNase7 could be used as a biomarker to identify patients with HCC who may benefit from anti-ROS1 treatment. LAY SUMMARY: Receptor tyrosine kinases are known to be involved in tumorigenesis and have been targeted therapeutically for a number of cancers, including hepatocellular carcinoma. ROS1 is the only such receptor with kinase activity whose ligand has not been identified. Herein, we show that RNase7 acts as a ligand to activate ROS1 signaling. This has important pathophysiological and therapeutic implications. Anti-ROS1 inhibitors could be used to treatment patients with hepatocellular carcinoma and high RNase7 levels.
Asunto(s)
Carcinogénesis , Carcinoma Hepatocelular , Crizotinib/farmacología , Neoplasias Hepáticas , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Ribonucleasas/metabolismo , Animales , Biomarcadores de Tumor/metabolismo , Carcinogénesis/efectos de los fármacos , Carcinogénesis/metabolismo , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/metabolismo , Ensayos de Migración Celular/métodos , Proliferación Celular/efectos de los fármacos , Perfilación de la Expresión Génica/métodos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Ligandos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/metabolismo , Ratones , Proteínas Tirosina Quinasas Receptoras/antagonistas & inhibidores , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Background and Objectives: To regain the ability of community ambulation is a meaningful goal for stroke patients. Recent research recommended that the distance accomplished during the six-minute walk test (≥205 m in 6MWT) is the fittest for defining community ambulation. Until now, there are few studies that have used the updated definition to investigate the related predictors. The aim of this study was to investigate the association between the admission clinical parameters and community ambulation measured by the 6MWT at discharge. The other aim was to find the admission Berg Balance Scale (BBS) cut-off score to discriminate between household or community ambulators. Materials and Methods: This cohort study collected the data of patients who entered the post-acute Care Cerebrovascular Diseases program. Multivariate logistic regression was used to identify significant predictors measured at admission that are associated with community ambulation, and a receiver operating characteristic was adopted to calculate the cut-off value for admission status. There were 120 participants included in this study, and 25% (n = 30) of them regained the ability of community ambulation at discharge. The BBS on admission was identified as the only significant predictor for community ambulation (odds ratio 1.06). Results: The optimal cut-off score for the BBS at admission was 29, and the area under the curve for BBS scores on admission when discriminating between household and community ambulators at discharge was 0.74. Conclusions: The admission BBS scores could be used to predict household and community ambulators at discharge in stroke patients. The results of this study could help clinical physicians set appropriate discharge goals early.
Asunto(s)
Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Estudios de Cohortes , Humanos , Alta del Paciente , Equilibrio Postural , CaminataRESUMEN
The American Nurses Credentialing Center (ANCC) manages Magnet Recognition Program® certification. Candidates for this certification are required to pass a review comprising six compulsory documents and 84 sets of written documents in five model components as well as an onsite appraisal. The Magnet Recognition Program® for medical institutes is currently regarded as the highest honor in the nursing field. The series of measures necessary to establish a Magnet-recognized hospital is described in this article. Our hospital began preparation for recognition in January 2016, with the application submitted in May 2017. The required measures include establishing a Professional Practice Model, Governance Council, and National Database of Nursing Quality Indicators as well as implementing a mentoring plan. ANCC approved Magnet Recognition Program® recognition for our hospital in May 2020, making ours the first Magnet-recognized hospital in Taiwan. The nursing staff shared their experiences on their Magnet journey. Magnet-recognition demonstrates that a hospital is adequately equipped and trained to provide patients with outstanding nursing care and to operate an excellent nursing practice environment.
Asunto(s)
Imanes , Personal de Enfermería en Hospital , Habilitación Profesional , Humanos , Taiwán , Estados UnidosRESUMEN
BACKGROUND: The process of entering motherhood is highly stressful for women, with 15-85% of new mothers experiencing postpartum blues or depression. This study was designed to evaluate the efficacy of a mindfulness-based childbirth and parenting program in improving psychological health during the postpartum period. METHODS: This research was a randomized controlled trial with single blinding. Recruitment began after the participating hospital granted formal approval. A total of 74 women between 13 and 28-weeks gestation were allocated either to the intervention group or to the comparison group. The intervention program included a series of eight, 3-h classes held once weekly and 1 day of 7-h silent meditation. Psychological health was assessed at baseline and 3-months postpartum. RESULTS: Significant differences in stress and depression were observed in both groups over time. Stress scores and depression scores were significantly better in the intervention group than in the comparison group at 3-months postpartum (F = 7.19, p = .009 and F = 7.36, p = .008, respectively). No significant difference between the groups was identified for mindfulness scores at 3-months postpartum. CONCLUSIONS: The intervention program effectively reduced postpartum self-perceived stress and depression, suggesting that this program provides acceptable and long-term benefits to women during pregnancy and the postpartum period. The teaching and practice of mindfulness meditation and parenting education during pregnancy may help reduce stress and depression in pregnant women as they transition into parenthood. TRIAL REGISTRATION: The ClinicalTrials.gov identifier for this study is: NCT03185910 . The study was retrospectively registered on 14 June 2017.
Asunto(s)
Depresión Posparto/prevención & control , Salud Mental , Atención Plena/métodos , Estrés Psicológico/prevención & control , Adulto , Depresión/psicología , Depresión Posparto/psicología , Femenino , Humanos , Periodo Posparto/psicología , Embarazo , Segundo Trimestre del Embarazo , Método Simple Ciego , Estrés Psicológico/psicología , Taiwán , Resultado del TratamientoRESUMEN
OBJECTIVES: To evaluate the effect of botulinum toxin type A (BTX)-induced masticatory muscle hypofunction on the maxillofacial suture bone growth of growing rats. SETTING AND SAMPLE POPULATION: Department of Orthodontics at Taipei Medical University. Forty-eight male 4-week-old Wistar rats were divided into four groups. The N group received injections of normal saline into each of the masseter and temporalis muscles. The M group received injections of normal saline into each of the temporalis muscle and injections of BTX into each of the masseter muscle. The T group received injections of normal saline into each of the masseter muscle and injections of BTX into each of the temporalis muscle. The MT group received injections of BTX into each of the masseter and temporalis muscles. MATERIAL & METHODS: Rats were sacrificed after 42 days of growth. Changes in body and muscle weight were measured. Anthropometric measurements of the maxillary arch, sutural bone mineral density and sutural bone deposition distances were recorded. Statistical comparisons were performed using analysis of variance. RESULTS: No significant change in body weight was found across groups. However, significant decreases were observed in muscle weight, anthropometric measurements, sutural bone mineral density and bone apposition distance in the BTX-injected group. CONCLUSIONS: Reduced masticatory muscle function in growing rats can affect maxillofacial suture bone growth.
Asunto(s)
Toxinas Botulínicas Tipo A , Animales , Desarrollo Óseo , Inyecciones Intramusculares , Masculino , Músculo Masetero , Músculos Masticadores , Ratas , Ratas WistarRESUMEN
Pathogenic bacteria such as Haemophilus influenzae, a major cause of lower respiratory tract diseases, must cope with a range of electrophiles generated in the host or by endogenous metabolism. Formaldehyde is one such compound that can irreversibly damage proteins and DNA through alkylation and cross-linking and interfere with redox homeostasis. Its detoxification operates under the control of HiNmlR, a protein from the MerR family that lacks a specific sensor region and does not bind metal ions. We demonstrate that HiNmlR is a thiol-dependent transcription factor that modulates H. influenzae response to formaldehyde, with two cysteine residues (Cys54 and Cys71) identified to be important for its response against a formaldehyde challenge. We obtained crystal structures of HiNmlR in both the DNA-free and two DNA-bound forms, which suggest that HiNmlR enhances target gene transcription by twisting of operator DNA sequences in a two-gene operon containing overlapping promoters. Our work provides the first structural insights into the mechanism of action of MerR regulators that lack sensor regions.
Asunto(s)
Proteínas Bacterianas/metabolismo , Proteínas de Unión al ADN/metabolismo , Formaldehído/metabolismo , Haemophilus influenzae/metabolismo , Compuestos de Sulfhidrilo/metabolismo , Proteínas Bacterianas/química , Cristalografía por Rayos X , ADN Bacteriano/química , ADN Bacteriano/metabolismo , Proteínas de Unión al ADN/química , ARN Polimerasas Dirigidas por ADN/metabolismo , Regulación Bacteriana de la Expresión Génica , Haemophilus influenzae/genética , Inactivación Metabólica/genética , Cinética , Modelos Moleculares , Regiones Operadoras Genéticas/genética , Regiones Promotoras Genéticas , Unión Proteica , Relación Estructura-Actividad , Factores de Transcripción/metabolismo , Transcripción GenéticaRESUMEN
Disulfide linkages play an important role in protein stability and activity. Thus, it is critical to characterize disulfide bonds to ensure the quality and function of protein pharmaceuticals. There are, however, problems associated with maintaining disulfide linkages in the conventional procedures that are used to digest a protein. In order to preserve enzyme activity during the digestion of a protein, it is commonly carried out at neutral to basic environment which increases the possibilities of disulfide bond scrambling. However, it is not easy to differentiate whether the scrambled disulfide linkages are initiated by the sample itself or whether they are induced during the protease digestion process. In this study, the optimum pH for minimizing disulfide bond rearrangements during the digestion process was determined. Three sets of proteases, trypsin plus Glu-C, Lys-C and thermolysin were used, followed by dimethyl labeling and mass spectrometry for a bevacizumab (Avastin) disulfide linkage analysis. No disulfide linkage scrambling was detected at pH6 when Lys-C or trypsin plus Glu-C were used as enzymes. When thermolysin was applied, some scrambled disulfide bonds were identified at pH5, 6 and 7. Nevertheless, there was less disulfide bond scrambling at a lower pH. All correct disulfide bonds on bevacizumab could be identified using this approach. The results demonstrated that by choosing the proper enzymes, using a lower pH environment for the digestion could reduce the degree of artifact disulfide scrambling.
Asunto(s)
Inhibidores de la Angiogénesis/química , Bevacizumab/química , Disulfuros/química , Termolisina/química , Tripsina/química , Secuencia de Aminoácidos , Biocatálisis , Concentración de Iones de Hidrógeno , Hidrólisis , Espectrometría de Masas , SolucionesAsunto(s)
Diabetes Mellitus , Pie Diabético , Humanos , Pie Diabético/cirugía , Nervios Periféricos , Dolor Postoperatorio , HemodinámicaRESUMEN
Accumulation of amyloid fibrils is one of the likely key factors leading to the development of Alzheimer's disease and other amyloidosis associated diseases. Magnetic nanoparticles (NPs) have been developed as promising medical materials for many medical applications. In this study, we have explored the effects of Fe3O4 NPs on the fibrillogenesis process of insulin fibrils. When Fe3O4 NPs were co-incubated with insulin, Fe3O4 NPs had no effect on the structural transformation into amyloid-like fibrils but had higher affinity toward insulin fibrils. We demonstrated that the zeta potential of insulin fibrils and Fe3O4 NPs were both positive, suggesting the binding forces between Fe3O4 NPs and insulin fibrils were van der Waals forces but not surface charge. Moreover, a different amount of Fe3O4 NPs added had no effect on secondary structural changes of insulin fibrils. These results propose the potential use of Fe3O4 NPs as therapeutic agents against diseases related to protein aggregation or contrast agents for magnetic resonance imaging.
Asunto(s)
Nanopartículas de Magnetita , Amiloide , InsulinaRESUMEN
Tourniquets are often needed for optimized phalangeal surgeries. However, few surgeons forget to remove them and caused ischemic injuries. We have a modified method to create a safe finger tourniquet for short duration finger surgeries, which can avoid such tragedy. It is done by donning a glove, cutting the tip of the glove over the finger of interest, and rolling the glove finger to the base. From 2010 to 2013, approximately 54 patients underwent digital surgical procedures with our safe finger tourniquet. Because the glove cannot be forgotten to be removed, the tourniquet must be released and removed. This is a simple and efficient way to apply a safe finger tourniquet by using hand rubber glove for a short-term bloodless finger surgery and can achieve an excellent surgical result.
Asunto(s)
Traumatismos de los Dedos/cirugía , Guantes Quirúrgicos , Torniquetes , Estudios de Seguimiento , Humanos , Seguridad del Paciente , Torniquetes/efectos adversosRESUMEN
Nuclear localization signals (NLSs) contain one or two clusters of basic residues and are recognized by the import receptor importin-α. There are two NLS-binding sites (major and minor) on importin-α and the major NLS-binding site is considered to be the primary binding site. Here, we used crystallographic and biochemical methods to investigate the binding between importin-α and predicted 'minor site-specific' NLSs: four peptide library-derived peptides, and the NLS from mouse RNA helicase II/Guα. The crystal structures reveal that these atypical NLSs indeed preferentially bind to the minor NLS-binding site. Unlike previously characterized NLSs, the C-terminal residues of these NLSs form an α-helical turn, stabilized by internal H-bond and cation-π interactions between the aromatic residues from the NLSs and the positively charged residues from importin-α. This helical turn sterically hinders binding at the major NLS-binding site, explaining the minor-site preference. Our data suggest the sequence RXXKR[K/X][F/Y/W]XXAF as the optimal minor NLS-binding site-specific motif, which may help identify novel proteins with atypical NLSs.
Asunto(s)
Señales de Localización Nuclear/química , ARN Helicasas/química , alfa Carioferinas/química , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Ratones , Simulación del Acoplamiento Molecular , Datos de Secuencia Molecular , Mutación , Señales de Localización Nuclear/genética , Señales de Localización Nuclear/metabolismo , Unión Proteica , Estructura Terciaria de Proteína , ARN Helicasas/genética , ARN Helicasas/metabolismo , alfa Carioferinas/genética , alfa Carioferinas/metabolismoRESUMEN
In the classical nucleocytoplasmic import pathway, nuclear localization signals (NLSs) in cargo proteins are recognized by the import receptor importin-α. Importin-α has two separate NLS binding sites (the major and the minor site), both of which recognize positively charged amino acid clusters in NLSs. Little is known about the molecular basis of the unique features of the classical nuclear import pathway in plants. We determined the crystal structure of rice (Oryza sativa) importin-α1a at 2-Å resolution. The structure reveals that the autoinhibitory mechanism mediated by the importin-ß binding domain of importin-α operates in plants, with NLS-mimicking sequences binding to both minor and major NLS binding sites. Consistent with yeast and mammalian proteins, rice importin-α binds the prototypical NLS from simian virus 40 large T-antigen preferentially at the major NLS binding site. We show that two NLSs, previously described as plant specific, bind to and are functional with plant, mammalian, and yeast importin-α proteins but interact with rice importin-α more strongly. The crystal structures of their complexes with rice importin-α show that they bind to the minor NLS binding site. By contrast, the crystal structures of their complexes with mouse (Mus musculus) importin-α show preferential binding to the major NLS binding site. Our results reveal the molecular basis of a number of features of the classical nuclear transport pathway specific to plants.
Asunto(s)
Cristalografía por Rayos X/métodos , Señales de Localización Nuclear/metabolismo , Oryza/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , alfa Carioferinas/química , alfa Carioferinas/metabolismo , Sitios de Unión , Señales de Localización Nuclear/química , Estructura Secundaria de Proteína , Estructura Terciaria de ProteínaRESUMEN
Structure transition cascade: Insulin fibrils undergo a secondary structural transition-from the α-rich to the ß-rich form-upon progressively increasing the incubation time from 0.5 to ten hours. Atomic force microscopy measurements show that the fibril surface chemistry changes from hydrophilic to hydrophobic and the aggregation rate increases fivefold.
Asunto(s)
Amiloide/química , Insulina/química , Interacciones Hidrofóbicas e Hidrofílicas , Microscopía de Fuerza Atómica/métodos , Estructura Secundaria de ProteínaRESUMEN
BACKGROUND & PROBLEMS: According to current surveys conducted between September and December 2011, the accuracy of primary caregiver-administered Home Total Parenteral Nutrition Care (HTPNC) was 62.0%. Further, nursing staffs provide instruction on HTPNC to only 22.2% of caregivers responsible for administering HTPNC. Main related causes were: (1) difficult to comprehend health education tools; (2) inconsistent nursing guidelines; (3) a lack of relevant standard operating procedures; and (4) poor caregiver adoption of TPN skills. PURPOSE: This project was developed to (1) increase the accuracy of primary caregiver-administered HTPNC to 90% and (2) increase the percentage of nurse-administered HTPNC to 90%. RESOLUTIONS: We developed appropriate nursing guidelines, created a health education CD-ROM with input from a cross-disciplinary team and total parenteral nutrition focus group, designed reusable teaching model aids for repetitive practice, and held regular group health education sessions. RESULTS: The nursing staff HTPNC instruction rate increased to 100%. Caregiver HTPNC implementation accuracy increased to 100% prior to patient discharge. CONCLUSIONS: This approach was successful in achieving its stated goals. Further, using reusable teaching model aids may reduce caregiver anxiety and increase caregiver confidence. The greatest benefit of this project was its extension of teaching model aids to relevant units, allowing for routine monitoring by the department of nursing quality management.
Asunto(s)
Cuidadores/educación , Educación en Salud , Nutrición Parenteral Total en el Domicilio , Humanos , EnseñanzaRESUMEN
Several poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) are approved by FDA to treat cancer with BRCA mutations. BRCA mutations are considered to fuel a PARPi killing effect by inducing apoptosis. However, resistance to PARPi is frequently observed in the clinic due to an incomplete understanding on the molecular basis of PARPi function and a lack of good markers, beyond BRCA mutations, to predict response. Here, we show that gasdermin C (GSDMC) sensitized tumor cells to PARPi in vitro and in immunocompetent mice and caused durable tumor regression in an immune-dependent manner. A high expression level of GSDMC predicted better response to PARPi treatment in patients with triple-negative breast cancer (TNBC). PARPi treatment triggered GSDMC/caspase-8-mediated cancer cell pyroptosis (CCP) that enhanced PARPi killing of tumor cells. GSDMC-mediated CCP increased memory CD8+ T cell population in lymph node (LN), spleen, and tumor and, thus, promoted cytotoxic CD8+ T cell infiltration in the tumor microenvironment. T cell-derived granzyme B (GZMB) activated caspase-6, which subsequently cleaved GSDMC to induce pyroptosis. Interestingly, IFN-γ induced GSDMC expression, which, in turn, enhanced the cytotoxicity of PARPi and T cells. Importantly, GSDMC promoted tumor clearance independent of BRCA deficiency in multiple cancer types with PARPi treatment. This study identifies a general marker and target for PARPi therapy and offers insights into the mechanism of PARPi function.
Asunto(s)
Neoplasias , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Humanos , Animales , Ratones , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Gasderminas , Neoplasias/genética , Apoptosis , Piroptosis , Microambiente Tumoral , Biomarcadores de Tumor/genéticaRESUMEN
The theories for substrate recognition in enzyme catalysis have evolved from lock-key to induced fit, then conformational selection, and conformational selection followed by induced fit. However, the prevalence and consensus of these theories require further examination. Here we use cryogenic electron microscopy and African swine fever virus type 2 topoisomerase (AsfvTop2) to demonstrate substrate binding theories in a joint and ordered manner: catalytic selection by the enzyme, conformational selection by the substrates, then induced fit. The apo-AsfvTop2 pre-exists in six conformers that comply with the two-gate mechanism directing DNA passage and release in the Top2 catalytic cycle. The structures of AsfvTop2-DNA-inhibitor complexes show that substantial induced-fit changes occur locally from the closed apo-conformer that however is too far-fetched for the open apo-conformer. Furthermore, the ATPase domain of AsfvTop2 in the MgAMP-PNP-bound crystal structures coexist in reduced and oxidized forms involving a disulfide bond, which can regulate the AsfvTop2 function.