alanine

丙氨酸
  • 文章类型: Journal Article
    在快速抗逆转录病毒治疗(ART)的背景下,缺乏比替格拉韦/恩曲他滨/替诺福韦艾拉酚胺(BIC/F/TAF;B)和达瑞那韦/科比司他/恩曲他滨/替诺福韦艾拉酚胺(DRV/c/F/TAF;D)的头对头数据。这项研究,BIC-T&T,在英国测试和治疗设置中评估B与D的疗效和耐受性。
    BIC-T&T是随机的,开放标签,多中心,研究参与者在基线实验室前HIV-1确诊后14天内开始ART.
    主要终点是第12周的病毒学应答(HIVRNA<50拷贝/mL),通过从治疗开始到第12周的病毒载量测定中记录的log10HIVRNA的时间加权平均变化,使用双样本Wilcoxon秩和检验。
    36名参与者被随机分组:94%为男性,53%白人;平均(SD)年龄为35岁(11.8)。基线平均(±SD)log10HIV-RNA为4.79(±0.87)log10拷贝/mL和CD4505(±253)细胞/mm3。从确认的HIV诊断到开始ART的平均(±SD)时间为7.9(±3.7)天。与D相比,B从治疗开始到第12周的log10HIVRNA的时间加权平均下降幅度明显更大(3.1vs.2.6log10拷贝/mL,p<0.001)。两种方案均表现出良好的耐受性,很少出现实验室异常,并且没有3或4级不良事件。
    在ART启动背景下的首次头对头研究中,与DRV/c/F/TAF相比,BIC/F/TAF从基线到第12周的HIVRNA下降速度明显更快。
    UNASSIGNED: Head-to-head data for bictegravir/emtricitabine/tenofovir alafenamide (BIC/F/TAF; B) and darunavir/cobicistat/emtricitabine/tenofovir alafenamide (DRV/c/F/TAF; D) are lacking in the context of rapid antiretroviral therapy (ART) initiation. This study, BIC-T&T, evaluates the efficacy and tolerability of B vs D in a UK test-and-treat setting.
    UNASSIGNED: BIC-T&T was a randomised, open-label, multi-centre, study in which participants initiated ART within 14 days after confirmed HIV-1 diagnosis before baseline laboratory.
    UNASSIGNED: The primary endpoint is the virological response (HIV RNA < 50copies/mL) at week 12 by time-weighted average change in log10 HIV RNA recorded in viral load assays from treatment initiation to week 12, using two-sample Wilcoxon rank-sum test.
    UNASSIGNED: 36 participants were randomised: 94% were male, 53% white; mean (SD) age was 35 years (11.8). Baseline mean (±SD) log10 HIV-RNA was 4.79 (± 0.87) log10 copies/mL and CD4 505 (±253) cells/mm3. The mean (±SD) time from confirmed HIV diagnosis to ART initiation was 7.9 (± 3.7) days. The time-weighted mean decrease in log10 HIV RNA from treatment initiation to week 12 was significantly greater in B in comparison to D (3.1 vs. 2.6 log10 copies/mL, p < 0.001). Both regimens demonstrated good tolerability with infrequent laboratory abnormalities and no grade 3 or 4 adverse events.
    UNASSIGNED: In this first head-to-head study in the context of ART initiation, HIV RNA decline from baseline to week 12 was significantly more rapid for BIC/F/TAF compared with DRV/c/F/TAF.
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  • 文章类型: Journal Article
    Remdesivir治疗在新冠肺炎的早期阶段被宣布为有效的。在339例患者中(男性55.8%,年龄71(59;77)岁)具有可检测的病毒载量,140例接受了雷米西韦治疗(其中103例在ICU,57例免疫抑制),并与199例患者(其中82例在ICU,28例免疫抑制)进行了回顾性比较,这些患者因晚期Covid-19而被拒绝治疗。通过检测血清中的核衣壳抗原来估计病毒载量(n=155,中位数217(28;1524)pg/ml),痰中的抗原(n=18,COI18(4.6;32)),鼻咽抗原(n=44,COI17(8;35))和实时PCR(n=122,Ct21(18;27))。在对混杂因素进行调整后,使用雷米西韦的患者有更好的12个月生存率(HR0.66(0.44;0.98),p=0.039),特别是当入住ICU时(HR0.49(0.29;0.81),p=0.006)。对于免疫功能低下的患者,差异无统计学意义(HR0.55(0.18;1.69),p=0.3)。其他最重要的混杂因素是年龄,入住ICU,机械通气,白细胞/淋巴细胞比率,入院肌酐与免疫抑制。单克隆抗体或先前接种疫苗的影响不显著。尽管频繁的免疫抑制,包括血液肿瘤疾病,淋巴细胞减少,和更高的炎症标记物在瑞德西韦组中,这些结果支持了在疾病严重程度高的患者中广泛使用的病毒载量估计值。
    Remdesivir therapy has been declared as efficient in the early stages of Covid-19. Of the 339 patients (males 55.8%, age 71(59;77) years) with a detectable viral load, 140 were treated with remdesivir (of those 103 in the ICU and 57 immunosuppressed) and retrospectively compared with 199 patients (of those 82 in the ICU and 28 immunosuppressed) who were denied therapy due to advanced Covid-19. The viral load was estimated by detecting nucleocapsid antigen in serum (n = 155, median 217(28;1524)pg/ml), antigen in sputum (n = 18, COI 18(4.6;32)), nasopharyngeal antigen (n = 44, COI 17(8;35)) and the real-time PCR (n = 122, Ct 21(18;27)). After adjustment for confounders, patients on remdesivir had better 12-month survival (HR 0.66 (0.44;0.98), p = 0.039), particularly when admitted to the ICU (HR 0.49 (0.29;0.81), p = 0.006). For the immunocompromised patients, the difference did not reach statistical significance (HR 0.55 (0.18;1.69), p = 0.3). The other most significant confounders were age, ICU admission, mechanical ventilation, leukocyte/lymphocyte ratio, admission creatinine and immunosuppression. The impact of monoclonal antibodies or previous vaccinations was not significant. Despite frequent immune suppression including haemato-oncology diseases, lymphopenia, and higher inflammatory markers in the remdesivir group, the results support remdesivir administration with respect to widely available estimates of viral load in patients with high illness severity.
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  • 文章类型: Journal Article
    背景:在大流行期间,严重急性呼吸道综合征冠状病毒2(SARS-CoV-2)突变,导致疾病的严重程度和药物的治疗效果相应的变化。本研究旨在使用真实世界数据,根据每种变体的患病率,介绍治疗方法的实际使用和临床结果。
    方法:我们分析了2020年2月1日至2022年6月30日确认2019年冠状病毒病(COVID-19)后入住釜山医疗中心的成年患者的电子病历。选择疾病进展风险较高的轻中度COVID-19患者作为研究对象,根据变体将时间段分类为祖先菌株,Delta变体,或Omicron变体。我们按时间段比较了药物使用状况和临床结果。
    结果:在所有3,091名患者中,糖皮质激素是最常用的治疗方法(56.0%),在Delta变体中使用最频繁(93.0%),其次是Omicron变体(42.9%)和祖先菌株(21.2%)。Regdanvimab在Delta变体(82.9%)和祖先菌株(76.8%)中占大多数治疗用途,而在Omicron变异期使用频率最高的是remdesivir(68.9%).死亡或疾病加重的复合结局按Delta变体的顺序排序,Omicron变体,和祖先菌株(14.5、11.9和6.0%,分别,P<0.001)。
    结论:Regdanvimab主要在祖先菌株期间使用,在Delta变异期,regdanvimab加皮质类固醇,在Omicron变异期和remdesivir.Delta变种的死亡率或疾病加重率最高,其次是Omicron变体和祖先菌株。
    BACKGROUND: During the pandemic period, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutated, leading to changes in the disease\'s severity and the therapeutic effect of drugs accordingly. This study aimed to present the actual use of therapeutics and clinical outcomes based on the prevalence of each variant using real-world data.
    METHODS: We analyzed the electronic medical records of adult patients admitted to Busan Medical Center after confirming coronavirus disease 2019 (COVID-19) from February 1, 2020, to June 30, 2022. Patients with mild-to-moderate COVID-19 who were at a high risk of disease progression were selected as study subjects, and the time period was classified according to the variants as ancestral strain, Delta variant, or Omicron variant. We compared drug use status and clinical outcomes by time period.
    RESULTS: Among all 3,091 patients, corticosteroids were the most commonly used therapy (56.0%), being used most frequently in the Delta variant (93.0%), followed by the Omicron variant (42.9%) and ancestral strain (21.2%). Regdanvimab accounted for the majority of therapeutic use in the Delta variant (82.9%) and ancestral strain (76.8%), whereas remdesivir was most frequently used during the Omicron variant period (68.9%). The composite outcomes of death or disease aggravation were ranked in the order of the Delta variant, Omicron variant, and ancestral strain (14.5, 11.9, and 6.0%, respectively, P < 0.001).
    CONCLUSIONS: Regdanvimab was primarily used during the ancestral strain period, regdanvimab plus corticosteroids during the Delta variant period, and remdesivir during the Omicron variant period. The rate of death or disease aggravation was highest in the Delta variant, followed by the Omicron variant and the ancestral strain.
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  • 文章类型: Journal Article
    D-丙氨酸的D-氨基酸,D-谷氨酸,和D-天冬氨酸增加清酒的品尝评价得分,一种日本传统的酒精饮料。清酒是使用种子糊状物酿造的,用于酿造酵母的生长而没有污染微生物的生长。使用乳酸菌生长以降低pH值酿造Kimoto。与使用SokujyoSyubo(Moto)方法酿造的清酒相比,使用Kimoto方法酿造的清酒还具有丰富的味道和更高的品尝评价评分,其中添加乳酸而不是使用乳酸菌生长。D-丙氨酸,D-谷氨酸,清酒中的D-天冬氨酸具有增加品尝评价分数的功能。它们分别通过乳酸菌中的酶转化为丙氨酸消旋酶(EC5.1.1.1),谷氨酸消旋酶(EC5.1.1.3),和天门冬氨酸消旋酶(EC5.1.1.13)在KimotoMash中。在这里,D-丙氨酸的同时测定方法,D-谷氨酸,和D-天冬氨酸解释。调节至碱度的样品溶液通过仅用于L-氨基酸的L-FDLA溶液衍生化。结果表明,对于D-丙氨酸,D-谷氨酸,和D-天冬氨酸,这种方法可以很容易地分析他们使用昂贵的或专门的设备。
    The D-amino acids of D-alanine, D-glutamic acid, and D-aspartic acid increase tasting evaluation scores of Sake, a Japanese traditional alcohol beverage. Sake is brewed using seed mash for growth of brewing yeast without growth of contaminating microorganisms. Kimoto is brewed using lactic acid bacteria growth to decrease pH. Sake brewed using the Kimoto method also has a rich taste and a higher tasting evaluation score than Sake brewed using the Sokujyo Syubo (Moto) method, which adds lactic acid instead of using lactic acid bacteria growth. D-alanine, D-glutamic acid, and D-aspartic acid in Sake have the function of increasing tasting evaluation scores. They are converted by enzymes in lactic acid bacteria respectively as alanine racemase (EC 5.1.1.1), glutamate racemase (EC 5.1.1.3), and aspartate racemase (EC 5.1.1.13) in Kimoto Mash. Herein, simultaneous assay methods for D-alanine, D-glutamic acid, and D-aspartic acid are explained. Sample solutions adjusted to alkalinity are derivatized by an L-FDLA solution only for L-amino acid. Results demonstrate that, for D-alanine, D-glutamic acid, and D-aspartic acid, this method can assay them easily using no expensive or specialized equipment.
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  • 文章类型: Journal Article
    背景:未经证实的COVID-19疗法的政治化和错误信息或虚假信息导致了向公众展示科学的沟通挑战,尤其是在公众恐惧和不确定的时候。
    目的:本研究旨在研究美国新闻中对3种未经证实的COVID-19疗法如何描述科学证据和不确定性,在开发经过验证的疗法和疫苗之前。
    方法:我们在2020年初对未经证实的COVID-19疗法进行了媒体分析。总共479次讨论了未经证实的COVID-19疗法(羟氯喹,remdesivir,和恢复期血浆)在2020年1月1日至2020年7月30日的传统和在线美国新闻报道中,对主题进行了系统分析,科学证据,证据细节和限制,安全,功效,和权威的来源。
    结果:大多数讨论包括科学证据(n=322,67%),尽管其中只有24%(n=116)提到了出版物。“政府”是remdesivir安全性和有效性声明的最常被命名的权威来源(n=43,35%),而“专家”声明则主要用于恢复期血浆(n=22,38%)。大多数关于羟氯喹的索赔(n=236,79%)是由一位知名人士提供的,其中97%(n=230)来自美国前总统特朗普。尽管有科学证据,许多关于安全性和有效性的声明是由非专家提出的.在讨论未经证实的COVID-19疗法时,很少有新闻报道表示科学上的不确定性,因为新闻报道中很少包含证据的局限性(n=125,26%),很少出现在标题(n=2,2%)或前导段落(n=9,9%;P<.001)中。
    结论:这些结果突出表明,尽管新闻报道中对科学证据的讨论相对频繁,科学不确定性很少被报道,很少出现在突出的标题和导语段落中。
    BACKGROUND: Politicization and misinformation or disinformation of unproven COVID-19 therapies have resulted in communication challenges in presenting science to the public, especially in times of heightened public trepidation and uncertainty.
    OBJECTIVE: This study aims to examine how scientific evidence and uncertainty were portrayed in US news on 3 unproven COVID-19 therapeutics, prior to the development of proven therapeutics and vaccines.
    METHODS: We conducted a media analysis of unproven COVID-19 therapeutics in early 2020. A total of 479 discussions of unproven COVID-19 therapeutics (hydroxychloroquine, remdesivir, and convalescent plasma) in traditional and online US news reports from January 1, 2020, to July 30, 2020, were systematically analyzed for theme, scientific evidence, evidence details and limitations, safety, efficacy, and sources of authority.
    RESULTS: The majority of discussions included scientific evidence (n=322, 67%) although only 24% (n=116) of them mentioned publications. \"Government\" was the most frequently named source of authority for safety and efficacy claims on remdesivir (n=43, 35%) while \"expert\" claims were mostly mentioned for convalescent plasma (n=22, 38%). Most claims on hydroxychloroquine (n=236, 79%) were offered by a \"prominent person,\" of which 97% (n=230) were from former US President Trump. Despite the inclusion of scientific evidence, many claims of the safety and efficacy were made by nonexperts. Few news reports expressed scientific uncertainty in discussions of unproven COVID-19 therapeutics as limitations of evidence were infrequently included in the body of news reports (n=125, 26%) and rarely found in headlines (n=2, 2%) or lead paragraphs (n=9, 9%; P<.001).
    CONCLUSIONS: These results highlight that while scientific evidence is discussed relatively frequently in news reports, scientific uncertainty is infrequently reported and rarely found in prominent headlines and lead paragraphs.
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  • 文章类型: Journal Article
    目的:氨基酸代谢的重编程与启动和促进肿瘤的形成和生长有关。因此,人们对靶向氨基酸代谢的抗癌疗法越来越感兴趣。在开发针对神经胶质瘤的个性化治疗方法时,体内质子磁共振波谱(MRS)是一种有价值的无创性监测肿瘤代谢的工具。这里,我们评估了MRS检测到的脑氨基酸和肌醇作为神经胶质瘤的潜在诊断和预后生物标志物.
    方法:我们测量了丙氨酸,甘氨酸,谷氨酸,谷氨酰胺,使用短和长回声时间单体素PRESSMRS序列在38例MRI怀疑的神经胶质瘤患者中和肌醇。丙氨酸的可检测性,甘氨酸,和肌醇和(谷氨酸+谷氨酰胺)/总肌酸比率针对患者的IDH突变状态进行评估,CNSWHO等级,和总体生存率。
    结果:虽然检测到丙氨酸和未检测到肌醇与IDH野生型(分别为p=0.0008,p=0.007)和WHO4级(分别为p=0.01,p=0.04)显着相关,甘氨酸检测与两者均无显著相关性.WHO4级的(谷氨酸谷氨酰胺)/总肌酸的比率明显高于2和3级。我们发现,丙氨酸检测的神经胶质瘤患者的总生存期明显缩短(p=0.00002)。
    结论:关注MRS中的氨基酸可以提高其在胶质瘤中的诊断和预后价值。丙氨酸,即使在脂质存在的情况下,在长TE下也可见,可能是总体生存率的相关指标。
    OBJECTIVE: Reprogramming of amino acid metabolism is relevant for initiating and fueling tumor formation and growth. Therefore, there has been growing interest in anticancer therapies targeting amino acid metabolism. While developing personalized therapeutic approaches to glioma, in vivo proton magnetic resonance spectroscopy (MRS) is a valuable tool for non-invasive monitoring of tumor metabolism. Here, we evaluated MRS-detected brain amino acids and myo-inositol as potential diagnostic and prognostic biomarkers in glioma.
    METHODS: We measured alanine, glycine, glutamate, glutamine, and myo-inositol in 38 patients with MRI-suspected glioma using short and long echo-time single-voxel PRESS MRS sequences. The detectability of alanine, glycine, and myo-inositol and the (glutamate + glutamine)/total creatine ratio were evaluated against the patients\' IDH mutation status, CNS WHO grade, and overall survival.
    RESULTS: While the detection of alanine and non-detection of myo-inositol significantly correlated with IDH wildtype (p = 0.0008, p = 0.007, respectively) and WHO grade 4 (p = 0.01, p = 0.04, respectively), glycine detection was not significantly associated with either. The ratio of (glutamate + glutamine)/total creatine was significantly higher in WHO grade 4 than in 2 and 3. We found that the overall survival was significantly shorter in glioma patients with alanine detection (p = 0.00002).
    CONCLUSIONS: Focusing on amino acids in MRS can improve its diagnostic and prognostic value in glioma. Alanine, which is visible at long TE even in the presence of lipids, could be a relevant indicator for overall survival.
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  • 文章类型: Journal Article
    卵菌真菌疫霉。作为影响印度橡胶树的最具破坏性的疾病之一,导致异常落叶(ALF)疾病构成了重大威胁。从喀拉拉邦西南季风季节收集的受ALF影响的样品中,总共获得了30株疫霉菌。疫霉分离株的菌落形态揭示了八种不同类型的生长模式,用星状,星状条纹,花瓣状图案迅速生长,而菊花图案生长缓慢。孢子囊为各种形状的乳头状到非乳头状,和孢子囊表现简单,简单的符号,或不规则的分支模式。高毒力分离株表现出花瓣状形态和快速生长速率。不管它们的毒力如何,所有分离株均对杀菌剂甲霜灵敏感。在体外条件下,来自橡胶的高毒力分离株(R17)在辣椒中引起严重感染,brinjal,和番茄有棕色的水浸皮损。内部转录间隔区(ITS)的序列分析和多位点系统发育,细胞色素c氧化酶1(COX1),热休克蛋白90(HSP90),核糖体蛋白L10(RPL10)证实该病原体为疫霉菌。全面了解P的形态和分子特征对于精确鉴定和未来的遗传变异研究至关重要。
    The Oomycetes fungus Phytophthora spp. which causes Abnormal leaf fall (ALF) disease poses a significant threat as one of the most devastating diseases affecting rubber trees in India. A total of 30 Phytophthora isolates were obtained from ALF-affected samples collected during the Southwest monsoon season of Kerala. The colony morphology of Phytophthora isolates revealed eight different types of growth patterns, with stellate, stellate striated, and petaloid patterns growing rapidly, whereas chrysanthemum pattern grew slowly. Sporangia were papillate to non-papillate in various shapes, and sporangiophores exhibited simple, simple sympodial, or irregularly branching patterns. Highly virulent isolates exhibited petaloid morphology and rapid growth rates. Regardless of their virulence, all isolates showed susceptibility to the fungicide metalaxyl. Under in vitro conditions, the highly virulent isolate (R17) from rubber caused severe infections in chili, brinjal, and tomato with brown water-soaked lesions. Sequence analysis and multi-locus phylogeny of Internal transcribed spacer (ITS), cCytochrome c oxidase 1 (COX 1), Heat shock protein 90 (HSP 90), and Ribosomal protein L10 (RPL 10) confirmed the pathogen as Phytophthora meadii. A comprehensive understanding of both morphological and molecular traits of P. meadii is crucial for precise identification and future genetic variability studies.
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  • 文章类型: Journal Article
    这项研究的目的是合成和评估载有雷米西韦(RDV)的纳米结构脂质载体(NLC),以控制其在COVID-19患者中的副作用。由于RDV在血液中的溶解度低,半衰期短,使用磺丁基醚-β-环糊精制备可注射制剂。然而,它可以在肾脏中积聚并导致肾脏损害。NLC通过增加药物溶解度和生物利用度改善疏水性药物如RDV的肠胃外递送。对于RDV-NLCs的合成,在快速搅拌下将含有Tween80的水相注射到脂质相中并进行超声处理。使用Box-Behnken设计和DesignExpert软件对实验条件进行了优化。最佳配方含有2.13%的总脂质,1%的总表面活性剂,和71分钟的热水浴时间。最佳配方显示粒径,多分散指数,zeta电位,和包封效率值151.0±1.7nm(从149.1到152.1),0.4±0.1(从0.3到0.5),-43.8±1.2mV(从-42.4到-44.7),和81.34±1.57%(从79.52到82.33%),分别。RDV-NLC在25℃下30天表现出可接受的稳定性,并与常用的静脉输液配伍48h。RDV-NLC的FE-SEM图像显示球形颗粒,平均直径为207nm。NLC-RDV制剂显示RDV持续释放,剂量倾泻风险低,尽量减少潜在的副作用。此外,RDV-NLC形式的RDV对健康正常肾细胞的细胞毒性较小,有望减少COVID-19患者的肾功能损害。
    The aim of this study was to synthesize and evaluate nanostructured lipid carriers (NLCs) loaded with Remdesivir (RDV) to control its side effects in COVID-19 patients. Due to the low solubility and short half-life of RDV in the blood, an injectable formulation was prepared using sulphobutylether-beta-cyclodextrin. However, it can accumulate in the kidney and cause renal impairment. NLCs improve the parenteral delivery of hydrophobic drugs such as RDV by increasing drug solubility and bioavailability. For the synthesis of RDV-NLCs, the aqueous phase containing Tween 80 was injected into the lipid phase under rapid stirring and was sonicated. The experimental conditions were optimized using Box-Behnken design and Design Expert software. The optimum formulation contained a total lipid of 2.13%, a total surfactant of 1%, and a hot bath time of 71 min. The optimum formulation showed particle size, polydispersity index, zeta potential, and entrapment efficiency values of 151.0 ± 1.7 nm (from 149.1 to 152.1), 0.4 ± 0.1 (from 0.3 to 0.5), -43.8 ± 1.2 mV (from -42.4 to -44.7), and 81.34 ± 1.57% (from 79.52 to 82.33%), respectively. RDV-NLCs showed acceptable stability for 30 days at 25 ℃ and were compatible with commonly used intravenous infusion fluids for 48 h. FE-SEM images of RDV-NLC showed spherical particles with a mean diameter of 207 nm. The NLC-RDV formulation showed a sustained release of RDV with a low risk of dose-dumping, minimizing potential side effects. In addition, RDV in the form of RDV-NLC causes less cytotoxicity to healthy normal kidney cells, which is expected to reduce renal impairment in COVID-19 patients.
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  • 文章类型: Journal Article
    天然存在的羊毛硫肽,通过各种酶翻译后修饰的肽,作为抗生素有着巨大的希望。尽管进行了广泛的生化和结构研究,肽修饰之前的事件仍然知之甚少。这里,我们确定了具有不同结构和功能特征的羊毛硫氨酸合成酶KC(LanKC)酶的不同亚类。我们证明了PneKC,这个子类的成员,形成二聚体并具有GTP酶活性。通过PneKC的三个低温EM结构,我们说明了肽PneA结合的不同阶段,从初始识别到完全绑定。我们的结构显示了与PneA核心肽和GTPγS复合的激酶结构域,磷酸结合裂解酶结构域,和非常规的环化酶结构域。PneA的前导肽与门环相互作用,从延伸到螺旋构象的过渡。我们确定了一个二聚化热点,并提出了一种在紧张和放松构象之间切换酶的“负协同性”机制。此外,我们确定了环化酶域中一个重要的盐桥,与常规环化酶结构域中的不同。这些残基在LanKC亚类中是高度保守的,并且是两个特征基序的一部分。这些结果揭示了羊毛硫肽修饰酶组装的潜在差异,并加深了我们对这些多功能酶中变构的理解。
    Naturally occurring lanthipeptides, peptides post-translationally modified by various enzymes, hold significant promise as antibiotics. Despite extensive biochemical and structural studies, the events preceding peptide modification remain poorly understood. Here, we identify a distinct subclass of lanthionine synthetase KC (LanKC) enzymes with distinct structural and functional characteristics. We show that PneKC, a member of this subclass, forms a dimer and possesses GTPase activity. Through three cryo-EM structures of PneKC, we illustrate different stages of peptide PneA binding, from initial recognition to full binding. Our structures show the kinase domain complexed with the PneA core peptide and GTPγS, a phosphate-bound lyase domain, and an unconventional cyclase domain. The leader peptide of PneA interact with a gate loop, transitioning from an extended to a helical conformation. We identify a dimerization hot spot and propose a \"negative cooperativity\" mechanism toggling the enzyme between tense and relaxed conformation. Additionally, we identify an important salt bridge in the cyclase domain, differing from those in in conventional cyclase domains. These residues are highly conserved in the LanKC subclass and are part of two signature motifs. These results unveil potential differences in lanthipeptide modification enzymes assembly and deepen our understanding of allostery in these multifunctional enzymes.
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  • 文章类型: Journal Article
    副本,来自RNA病毒,是保留必需病毒酶基因而缺乏关键结构蛋白基因的遗传构建体。一旦引入细胞,复制子RNA携带的基因被表达,RNA自我复制,然而,病毒颗粒生产不发生。通常,RNA复制子在体外转录,然后在细胞中电穿孔。然而,在DNA转染而不是RNA转染后在细胞中产生复制子将是有利的。在这项研究中,将在T7启动子控制下编码SARS-CoV-2复制子的细菌人工染色体(BAC)DNA转染到HEK293T细胞中,这些细胞被工程化以功能性表达T7RNA聚合酶(T7RNAP)。转染BACDNA后,我们观察到低,但该复制子携带的报告蛋白GFP和荧光素酶的可重复表达。报道蛋白的表达需要在转染之前使BACDNA线性化。此外,表达独立于T7RNAP。基因表达也对remdesivir治疗不敏感,这表明它不涉及复制子RNA的自我复制。在高度允许SARS-CoV-2感染的Calu-3细胞中获得了类似的结果。引人注目的是,SARS-CoV-2N蛋白的先前表达增强了转染的SARS-CoV-2RNA复制子的表达,但不增强复制子BACDNA的表达。总之,编码冠状病毒复制子的大DNA的转染通过未知的机制导致可重复的复制子基因表达。这些发现突出了从转染的复制子cDNA中表达复制子基因的新途径,为开发基于DNA的RNA复制子应用方法提供有价值的见解。
    Replicons, derived from RNA viruses, are genetic constructs retaining essential viral enzyme genes while lacking key structural protein genes. Upon introduction into cells, the genes carried by the replicon RNA are expressed, and the RNA self-replicates, yet viral particle production does not take place. Typically, RNA replicons are transcribed in vitro and are then electroporated in cells. However, it would be advantageous for the replicon to be generated in cells following DNA transfection instead of RNA. In this study, a bacterial artificial chromosome (BAC) DNA encoding a SARS-CoV-2 replicon under control of a T7 promoter was transfected into HEK293T cells engineered to functionally express the T7 RNA polymerase (T7 RNAP). Upon transfection of the BAC DNA, we observed low, but reproducible expression of reporter proteins GFP and luciferase carried by this replicon. Expression of the reporter proteins required linearization of the BAC DNA prior to transfection. Moreover, expression occurred independently of T7 RNAP. Gene expression was also insensitive to remdesivir treatment, suggesting that it did not involve self-replication of replicon RNA. Similar results were obtained in highly SARS-CoV-2 infection-permissive Calu-3 cells. Strikingly, prior expression of the SARS-CoV-2 N protein boosted expression from transfected SARS-CoV-2 RNA replicon but not from the replicon BAC DNA. In conclusion, transfection of a large DNA encoding a coronaviral replicon led to reproducible replicon gene expression through an unidentified mechanism. These findings highlight a novel pathway toward replicon gene expression from transfected replicon cDNA, offering valuable insights for the development of methods for DNA-based RNA replicon applications.
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