Photosynthetic Characteristics of Transgenic Rice Plants Overexpressing Maize Phosphoenopyruvate Carboxylase

用转PEPC、PPDK、NADP_ME、PEPC +PPDK 双基因水稻 (OryzasativaL .)及原种为材料 ,以光合酶活性、饱和光合速率及PSⅡ光化学效率 (Fv/Fm)为指标 ,研究了转PEPC基因水稻的光合生理特征。结果如下 :转PEPC基因水稻PEPC活性比原种提高 2 0倍 ;饱和光合速率比原种高 5 5 % ;用高光强或人工光氧化剂甲基紫精 (MV)处理后 ,与原种相比 ,转PEPC基因水稻光化学效率下降较少 ,证明其耐光抑制、耐光氧化能力增强 ,测定其光合日变化看出 :在 1d中不同时间 ,转PEPC基因水稻的光合速率均高于原种 ,且与PEPC活性的日变化有相似的趋势。上述结果为转PEPC基因水稻的生理机制和育种研究提供了依据和途径。

Preliminary Study on Phosphoenolpyruvate Carboxylase(PEPCase) Gene Introduced into Wheat

[ Objective] The aim of this study was to introduce Phosphoenolpyruvate Carboxylase （PEPCase） gene into common wheat Linyou 145. [ Method] With the material of common wheat Linyou 145, Phosphoenolpyruvate Carboxylase （PEPCase） gene was introduced into wheat embryo callus by the agrobacterium-mediated transformation system, and then analyzed through successive selection with selective medium con- taing gygrornycin to detect the gene at the molecular level. [Result] The hyg-resistant plants were obtained, and GUS histochemical staining showed the leaf of resistant plants was stained dark blue. The target bands appeared in PCR analysis. [ Conclusion] Phosphoenolpyruvate Car- boxylase （PEPCase） gene has been primarily introduced into the recipient material.

Identification and Expression Analysis of the Phosphoenolpyruvate Carboxylase Gene Family in Peanut (Arachis hypogaea L.)

Phosphoenolpyruvate carboxylase （PEPC） is widely distributed in plants and bacteria, and catalyzes the carboxylation of phosphoenolpyruvate to form oxaloacetate and inorganic phosphate. To investigate the molecular mechanisms of the regulation and control of peanut oil, with the degenerated primers and RACE-PCR approach, five PEPC genes were cloned from peanut, and designated as AhPEPC1, AhPEPC2, AhPEPC3, AhPEPC4, and AhPEPC5, respectively. The structure and phylogenetic analysis of PEPC protein indicated that AhPEPC1-4 genes encoded a typical plant-type PEPC-enzyme, and AhPEPC5 a bacterial-type. By real-time quantitative RT-PCR approach the expression pattern of each gene was detected in various tissues of normal and high oil-content peanut varieties. It was found that there was a lower expression level of AhPEPCs genes except for the AhPEPC2 in high-oil peanut than normal-oil peanut line. The results provide some fundamental information for the further investigation of plant PEPC proteins and their role in regulation of oil-content in peanut seeds.

Functional Analysis of the Phosphoenolpyruvate Carboxylase on the Lipid Accumulation of Peanut(Arachis hypogaea L.) Seeds

Phosphoenolpyruvate carboxylase（PEPC;EC 4.1.1.31） catalyses phosphoenolpyruvate（PEP） to yield oxaloacetate,which is involved in protein biosynthesis.Pyruvate kinase（PK;EC 2.7.1.40） catalyzes PEP to yield pyruvate,which is involved in fatty acid synthesis.In this study,five PEPC genes（AhPEPC1,AhPEPC2,AhPEPC3,AhPEPC4,and AhPEPC5） from peanut have been cloned.Using a quantitative real-time RT-PCR approach,the expression pattern of each gene was monitored during the seed development of four peanut varieties（E11,Hebeigaoyou,Naihan 1,and Huayu 26）.It was found that these five genes shared similar expression behaviors over the developmental stages of E11 with high expression levels at 30 and 40 d after pegging（DAP）;whereas these five genes showed irregular expression patterns during the seed development of Hebeigaoyou.In Naihan 1 and Huayu 26,the expression levels of the five genes remained relatively high in the first stage.The PEPC activity was monitored during the seed development of four peanut varieties and seed oil content was also characterized during whole period of seed development.The PEPC activity followed the oil accumulation pattern during the early stages of development but they showed a significantly negative correlation thereafter.These results suggested that PEPC may play an important role in lipid accumulation during the seed development of four peanut varieties tested.

Characterization of ribulose-1,5-bisphosphate carboxylase/oxygenase and transcriptional analysis of its related genes in Saccharina japonica(Laminariales,Phaeophyta)

Saccharina japonica is a common macroalga in sublittoral communities of cold seawater environments, and consequently may have highly efficient ribulose-1, 5-bisphosphate carboxylase/ oxygenase （Rubisco） activity for carbon assimilation. In our study, we cloned the full-length Rubisco gene from S.japonica （SJ-rbc）. It contained an open reading frame for a large subunit gene （SJ-rbcL） of 1 467 bp, a small subunit gene （SJ-rbcS） of 420 bp, and a SJ-rbcL/S intergenie spacer of 269 bp. The deduced peptides of SJ-rbcL and SJ-rbcS were 488 and 139 amino acids with theoretical molecular weights and isoelectric points of 53.97 kDa, 5.81 and 15,84 kDa, 4.71, respectively. After induction with 1 mmol/L isopropyl-β-D- thiogalactopyranoside for 5 h and purification by Ni2＋ affinity chromatography, electrophoresis and western blot detection demonstrated successful expression of the 55 kDa SJ-rbcL protein. Real-time quantitative PCR showed that the mRNA levels of SJ-rbcL in gametophytes increased when transferred into normal growth conditions and exhibited diurnal variations： increased expression during the day but suppressed expression at night. This observation implied that Rubisco played a role in normal gametophytic growth and development. In juvenile sporophytes, mRNA levels of SJ-rbcL, carbonic anhydrase, Calvin-Benson- Bassham cycle-related enzyme, and chloroplast light-harvesting protein were remarkably increased under continuous light irradiance. Similarly, expression of these genes was up-regulated under blue light irradiance at 350 umol/（m2.s）. Our results indicate that long-term white light and short-term blue light irradiance enhances juvenile sporophytic growth by synergistic effects of various photosynthetic elements.

Acetyl-CoA carboxylase inhibitors in non-alcoholic steatohepatitis: Is there a benefit?

De novo lipogenesis(DNL)plays an important role in the pathogenesis of hepatic steatosis and also appears to be implicated in hepatic inflammation and fibrosis.Accordingly,the inhibition of acetyl-CoA carboxylase,which catalyzes the ratelimiting step of DNL,might represent a useful approach in the management of patients with nonalcoholic fatty liver disease(NAFLD).Animal studies and preliminary data in patients with NAFLD consistently showed an improvement in steatosis with the use of these agents.However,effects on fibrosis were variable and an increase in plasma triglyceride levels was observed.Therefore,more longterm studies are needed to clarify the role of these agents in NAFLD and to determine their risk/benefit profile.

Photosynthetic Characteristics and Heterosis in Transgenic Hybrid Rice with Maize Phosphoenolpyruvate Carboxylase (pepc) Gene

Three F3 hybrids derived from the sterile rice lines Gang 46A, 776A and 2480A and the improved restorer line Shuhui 881 containing maize phosphoenolpyruvate carboxylase （pepc） gene were used to analyze the effect of pepc gene on the heterosis and photosynthetic characteristics, while the F3 obtained by crossing Shuhui 881 with the above three sterile lines served as controls. The dynamics of photosynthetic characteristics in leaves of three F1 with pepc gene and their controls were determined at the initial-tillering, maxium-tillering, elongation, initial-heading, heading, maturity stages, and other different times after flag leaf fully expanded. The PEPCase activities of the three F1 with pepc gene increased significantly as compared with control plants during the whole developmental stages. Moreover, the net photosynthesis rate （Pn） also increased to certain extent. The data showed that PEPCase activity was significantly correlated to Pn with a correlation coefficient of 0.6081. The photosynthetic indexes of the three F1 with pepc gene were obviously superior to respective controls in apparent quantum efficiency, light compensation point and carboxylation efficiency, while the CO2 compensation point was lower than that of corresponding control. The Pn of the three F1 with pepc gene at light saturation point and CO2 saturation point was also higher than that of control plants. in addition, the three F1 with pepc gene had an average increase of 37.10% in grain yields per plant in comparison with control plants. The results indicated that the photosynthetic characteristics of hybrid rice containing pepc gene had been improved to some extent due to the introduction of pepc gene.

Genetic Mutation of Vitamin K-dependent Gamma-glutamyl Carboxylase Domain in Patients with Calcium Oxalate Urolithiasis

To investigate the exon mutation of vitamin K-dependent gamma-glutamyl carboxylase （GGCX or VKDC） in patients with calcium oxalate urolithasis, renal cortex and peripheral blood samples were obtained from severe hydronephrosis patients （with or without calculi）, and renal tumor patients undergoing nephrectomy. GGCX mutations in all 15 exons were examined in 44 patients with calcium oxalate urolithiasis （COU） by polymerase chain reaction （PCR） and denatured high pressure liquid chromatography （DHPLC）, and confirmed by sequencing. Mutation was not found in all COU samples compared to the controls. These data demonstrated that functional GGCX mutations in all 15 exons do not occur in most COU patients. It was suggested that there may be no significant association between the low activity and mutation of GGCX in COU.

Cloning, Expression and Purification of Wheat Acetyl-CoA Carboxylases CT Domain in E. coil

The entire gene of carboxyltransferase（CT） domain of acetyl-CoA carboxylase（ACCase） from Chinese Spring wheat（CSW） plastid was cloned firstly, and the 2.3 kb gene was inserted into PET28a^＋ vector and expressed in E. coil in a soluble state. The （His）6 fusion protein was identified by SDS-PAGE and Western blot. The recombinant protein was purified by affinity chromatography, and the calculated molecular mass（Mr） was 88000. The results of the sequence analysis indicate that the cloned gene（GeneBank accession No. EU124675） was a supplement and revision of the reported ACCase CT partial cDNA from Chinese Spring wheat plastid. The recombinant protein will be significant for us to investigate the recognizing mechanism between ACCase and herbicides, and further to screen new herbicides.

Concomitant Increases of the Developing Seed Phosph<i>oenol</i>pyruvate Carboxylase Ac-tivity and the Seed Protein Content of Field-Grown Wheat with Nitrogen Supply

Wheat seed storage protein is of great importance for human food. To increase the contents of storage proteins effectively, nitrogen fertilizer at flowering stages is commonly applied. In our previous study, rice phosphoenolpyruvate carboxylase (PEPCase) activity in developing seeds was observed in response to nitrogen application at a flowering stage and was positively correlated to the response of the protein content in seeds of six cultivars. This observation might indicate that the seeds have a biological system for accepting nitrogen in seeds by using PEPCase. To test whether this physiological event occurs in wheat, we examined the PEPCase activity and protein content in field-grown wheat seeds under different nitrogen supply conditions. With only basal dressing, seeds showed lower PEPCase activity and protein content (both 0.90-fold) compared to seeds without basal fertilizer. With ammonium sulfate application at 8.3 and 25 g/m2 at a flowering stage, seeds showed higher PEPCase activity (1.08- and 1.17-fold, respectively) and protein content (1.15- and 1.42-fold, respectively), depending on the nitrogen level. We investigated the relationship between PEPCase activity and protein content in the seeds among four conditions. The effect of the nitrogen supply on PEPCase activity during grain-filling stages was validated by the results of a hydroponic culture experiment. Together the results demonstrate that our hypothesis seems to apply to field-grown wheat.

Detection of Acetyl-CoA Carboxylase （ACCase） Inhibitor Herbicides Resistance in Sterile Wild Oat （Avena sterilis L.） Using Agar Quick Test

This study was conducted using seeds in Petri dish containing agar medium in order to determine acetyl-CoA carboxylase （ACCase） herbicides resistance （R） in Avena sterilis that was grown in wheat fields at Adana province, Turkey. Seeds were collected from one large suspected field, where clodinafop-propargyl （Aryloxyphenoxypropionate “FOPs”） and pinoxaden （Phenylpyrazoline “DEN”） have been applied for many years. Susceptible （S） population was collected from the road side on the same region. Agar media of concentration 14 g/L was prepared and it was melted in microwave. Then the amount of 20 mL agar media was added into each Petri dish. Five seeds were placed on agar mediums containing discriminating dose of clodinafop and pinoxaden. Petri dishes were placed in growth incubator operating at 10 °C. After 15 d, both radicle and hypocotyl length were measured. The percentage of germinated seed and dose-response curves were determined. At these different concentration levels, there were more than 50% of R and less than 40% of S seed germinated for pinoxaden. However, for clodinafop, more than 60% of R and less than 50% of S seeds were germinated. At higher concentration levels, the populations of resistant and susceptible were not germinated for both herbicides. The resistance value of R population was then compared with that of the S biotype. From the resistance index （RI）, the population was more resistant to pinoxaden （7.43 for radicle and 2.47 for hypocotyl） than the clodinafop-propagyl （1.39 for radicle and 3.77 for hypocotyl）. The method provided a simple, quick and cost effective way to identify ACCase herbicides resistance in most grass weeds.

Differential effect of biotin on carboxylase activity and mice skeletal muscle metabolism

In mammalian skeletal muscle there are four carboxylases involved in several biochemical processes like gluconeogenesis, tricarboxylic acid cycle anaplerosis, metabolism of fatty acids and metabolism of various amino acids. It has been shown that biotin deficiency reduces body weight at the expense of muscular mass. When necessary, the liver uses skeletal muscle protein to provide glucose and amino acids to organs in need of such compounds. In this paper we analyzed carboxylase specific activities in hind limb skeletal muscle of 3 weeks old BALB/c male mice, at 0, 1, 4, 7, and 14 days of a specific diet with different biotin concentrations. Biotin was used at 0.0, 1.8 or 98.2 mg per kg of food;and was referred to as biotin deficient, sufficient and supplemented, respectively. Water and food supply and consumption by the three groups of mice were the same. Therefore, the observed effects were directly related to biotin ingestion. The body weight of biotin supplemented mice was the same as the body weight of mice in the biotin sufficient group, while biotin deficiency caused body weight reduction after 7 days of biotin depletion. We found that the total protein concentration in the vastus lateralis muscle is associated with the biotin content in the diet. After 7 days, the muscle total protein content was lower in mice of the biotin deficient group while it was higher in the mice from the biotin supplemented group

重庆地区马唐种群对2种乙酰辅酶A羧化酶抑制剂类除草剂的敏感性

为高效科学防除重庆地区马唐Digitaria sanguinalis(L.)Scop.,采用整株生物测定法,测定了不同马唐种群对2种乙酰辅酶A羧化酶抑制剂类除草剂的ED_(50)和相对抗性倍数(RI)。结果表明,不同马唐种群对噁唑酰草胺、烯草酮均产生了不同程度的抗性(相对敏感种群除外);DJSP02对噁唑酰草胺、烯草酮分别表现为中抗(RI=8.78)和低抗(RI=2.10),其ED_(50)分别为377.31 g/hm^(2)和37.97 g/hm^(2);DJSP03对噁唑酰草胺、烯草酮分别表现为低抗(RI=3.18)和中抗(RI=7.56),其ED_(50)分别为136.84 g/hm^(2)和136.93 g/hm^(2),均已产生了正交互抗性。因此,在对重庆地区抗性马唐种群进行防除时宜与其他类型的除草剂混用或交替使用。

Acetyl coenzyme A carboxylase modulates lipogenesis and sugar homeostasis in Blattella germanica

Lipid and sugar homeostasis is critical for insect development and survival.In this study,we characterized an acetyl coenzyme A carboxylase gene in Blattella germanica(BgACC)that is involved in both lipogenesis and sugar homeostasis.We found that BgACC was dominantly expressed in the fat body and integument,and was significantly upregulated after molting.Knockdown of BgACC in 5th-instar nymphs did not affect their normal molting to the next nymphal stage,but it caused a lethal phenotype during adult emergence.BgACC-RNA interference(RNAi)significantly downregulated total free fatty acid(FFA)and triacylglycerol(TAG)levels,and also caused a significant decrease of cuticular hydrocarbons(CHCs).Repression of BgACC in adult females affected the development of oocytes and resulted in sterile females,but BgACC-RNAi did not affect the reproductive ability of males.Interestingly,knockdown of BgACC also changed the expression of insulin-like peptide genes(BglLPs),which mimicked a physiological state of high sugar uptake.In addition,BgACC was upregulated when B.germanica were fed on a high sucrose diet,and repression of BgACC upregulated the expression of the glycogen synthase gene(BgGlyS).Moreover,BgACC-RNAi increased the circulating sugar levels and glycogen storage,and a longevity assay suggested that BgACC was important for the survival of B.germanica under conditions of high sucrose uptake.Our results confirm that BgACC is involved in multiple lipid biogenesis and sugar homeostasis processes,which further modulates insect reproduction and sugar tolerance.This study benefits our understanding of the crosstalk between lipid and sugar metabolism.

不同进化类型大豆品种光合碳代谢关键酶活性研究

光合碳代谢是大豆生长发育过程中基础的生理代谢途径,对其自身的产量和品质有重要的影响。为了探索大豆品种演化过程中光合特性的变化规律和碳代谢的演化趋势,本研究以野生、半野生、半栽培和栽培大豆品种为试验材料,对不同进化类型大豆光合特性以及光合碳代谢关键酶活性进行研究。结果表明:净光合速率、气孔导度、蒸腾速率、RuBP羧化酶活性和叶绿素含量在所有类型的大豆品种中均呈现单峰曲线变化,均以栽培型最高,最大值在R2期,栽培型净光合速率、叶绿素含量和RuBP羧化酶活性分别为24.2μmol·m^(-2)·s^(-1)、99.9 mg·g^(-1)和4.5μmol·g^(-1)·min^(-1)。碳代谢相关酶活性也均呈单峰曲线变化,蔗糖合成酶、蔗糖磷酸合成酶、淀粉合成酶、ADPG焦磷酸化酶和UDPG焦磷酸化酶活性最大值均出现在R2期,栽培型大豆品种的蔗糖合成酶和ADPG焦磷酸化酶活性显著高于其它类型品种,分别较野生、半野生、半栽培品种高203.4%、67.8%、49.2%和192.5%、142.4%和131.1%。各类型大豆叶片碳代谢相关酶活性,在V2和R2期与Pn呈显著或者极显著正相关,在R4、R6和R8期与Pn无显著相关性或呈负相关,随着大豆品种的演化,叶片光合碳同化能力改善,其中RuBP羧化酶、蔗糖合成酶和ADPG焦磷酸化酶活性增强幅度较高。研究结果可为大豆品种选育及高光效利用研究提供理论基础。

乙酰辅酶A羧化酶2通过调控细胞周期促进肝癌细胞增殖

目的:研究乙酰辅酶A羧化酶2(acetyl-co carboxylase 2,ACC2)对肝癌细胞增殖、迁移能力的影响以及其潜在的作用机制。方法:通过TCGA、GEO、CPTAC数据库对ACC2在肝癌(hepatocellular carcinoma,HCC)患者肝脏组织中的表达和预后价值进行分析。采用CRISPR-Cas9系统构建了ACC2敲低肝癌细胞系,观察肝癌细胞增殖、迁移能力以及细胞周期的变化,Western blot实验检测细胞周期相关蛋白的表达。结果:ACC2在肝癌组织中低表达(P<0.05)且与预后不良相关(P<0.05)。体外细胞功能学实验表明降低ACC2表达显著促进肝癌细胞增殖、迁移能力(P<0.05)。细胞周期流式分析显示敲低ACC2促进肝癌细胞周期G1/S期的转变(P<0.05),细胞周期相关蛋白中CyclinE2和p21的表达降低,而CyclinA2和p-RB的表达升高。结论:ACC2可以促进肝癌细胞增殖和迁移的能力,对细胞增殖的促进作用是通过加速肝癌细胞周期G1向S期的转化实现的。

敲低乙酰辅酶A羧化酶1对食管鳞状细胞癌KYSE450细胞迁移的影响及机制

目的探讨敲低乙酰辅酶A羧化酶1(ACC1)对食管鳞状细胞癌KYSE450细胞迁移能力的影响及机制。方法将对数生长期食管鳞状细胞癌KYSE450细胞随机分为shNC组、shACC1组、shNC+AEB071组及shACC1+AEB071组,shNC组KYSE450细胞转染空白质粒载体,shACC1组KYSE450细胞转染慢病毒质粒载体,shNC+AEB071组KYSE450细胞转染空白质粒载体后加入5μL浓度为2 mmoL·L^(-1)的蛋白激酶C抑制剂AEB071(终浓度为5μmoL·L^(-1)),shACC1+AEB071组KYSE450细胞转染慢病毒质粒载体后加入5μL浓度为2 mmoL·L^(-1)的蛋白激酶C抑制剂AEB071(终浓度为5μmoL·L^(-1))。Transwell法检测各组KYSE450细胞迁移能力;显微镜下观察各组KYSE450细胞形态学变化;Western blot检测4组KYSE450细胞中乙酰辅酶A羧化酶1(ACC1)、组蛋白H3(H3)、乙酰化的组蛋白H3第9赖氨酸(H3K9Ac)及上皮-间质转化(EMT)标志物β-连环蛋白(β-catenin)、波形蛋白(Vimentin)以及锌指转录因子(Snail)等的表达。结果shACC1组KYSE450细胞迁移数显著高于shNC组(P<0.05);shNC+AEB071组与shNC组KYSE450细胞迁移数比较差异无统计学意义(P>0.05);shACC1+AEB071组KYSE450细胞迁移数显著低于shACC1组(P<0.05)。shNC组KYSE450细胞呈椭圆形上皮样细胞形态,shACC1组KYSE450细胞呈类似于梭形的间质样细胞形态,shNC+AEB071组和shACC1+AEB071组KYSE450细胞呈椭圆形上皮样细胞形态。shACC1组KYSE450细胞中ACC1相对表达量显著低于shNC组(P<0.05),β-catenin、Vimentin、Snail的相对表达量及H3K9Ac/H3比值显著高于shNC组(P<0.05);shNC+AEB071组与shNC组KYSE450细胞中ACC1、β-catenin、Vimentin、Snail相对表达量及H3K9Ac/H3比值比较差异无统计学意义(P>0.05);shACC1+AEB071组KYSE450细胞中β-catenin、Vimentin、Snail的相对表达量及H3K9Ac/H3比值显著低于shACC1组(P<0.05);shACC1+AEB071组与shACC1组KYSE450细胞中ACC1相对表达量比较差异无统计学意义(P>0.05)。结论敲低ACC1可促进食管鳞状细胞癌KYSE450细胞的迁移,从而促进肿瘤的进展,其机制可能是通过蛋白激酶C相关信号通路介导的。

3-甲基巴豆酰辅酶A羧化酶缺乏症6例患儿的临床特征及遗传学分析

目的探讨3-甲基巴豆酰辅酶A羧化酶缺乏症(3-methylcrotonyl-coenzyme A carboxylase deficiency,MCCD)患儿的临床及遗传学特征。方法回顾性分析2018年1月-2023年10月就诊于郑州大学附属儿童医院的6例MCCD患儿的临床表现及基因检测结果。结果6例MCCD患儿中,男性4例,女性2例,平均就诊年龄为7 d,平均确诊年龄为45 d。1例小便气味异常,5例无临床症状。6例患儿血3-羟基异戊酰肉碱、尿3-羟基异戊酸、3-甲基巴豆酰甘氨酸均增高,5例伴游离肉碱降低。共检出MCCC1基因变异6个:c.1630del(p.R544Dfs*2)、c.269A>G(p.D90G)、c.1609T>A(p.F537I)、c.639+2T>A、c.761+1G>T、c.1331G>A(p.R444H),以及MCCC2基因变异3个:c.838G>T(p.D280Y)、c.592C>T(p.Q198*,366)、c.1342G>A(p.G448A),其中MCCC1基因c.269A>G(p.D90G)、c.1609T>A(p.F537I)未见文献报道。1例为母源性MCCD,患儿携带来自母亲的一个杂合变异。5例伴游离肉碱降低患儿予补充左卡尼汀,末次随访时游离肉碱均恢复至正常水平。结论MCCC1基因c.269A>G(p.D90G)、c.1609T>A(p.F537I)为新发现的变异,丰富了MCCC1基因变异谱。血氨基酸及酰基肉碱谱和尿有机酸谱联合基因检测有助于MCCD早期诊断和治疗,并为遗传咨询提供参考。

白灵侧耳ACC基因克隆及表达分析

通过克隆白灵侧耳(Pleurotus tuoliensis)乙酰辅酶A羧化酶(acetyl-CoA carboxylase,ACC)基因,采用生物信息学方法预测白灵侧耳ACC的理化性质、信号肽、跨膜结构域、亚细胞定位、二级结构、三级结构和保守结构域;基于白灵侧耳ACC与灰盖鬼伞(Coprinopsis cinerea)、糙皮侧耳(P.ostreatus)、香菇(Lentinula edodes)、刺芹侧耳(P.eryngii)等16个物种的氨基酸序列,采用邻接法构建系统发育树;通过荧光定量PCR测定pH为3、4、5、6、7、8、9、10、11、12时的白灵侧耳ACC的相对表达量。结果表明:白灵侧耳ACC DNA长度为7366 bp,包含12个内含子和13个外显子,cDNA长度为6696 bp,共编码2231个氨基酸残基,相对分子质量为247400,白灵侧耳ACC为酸性、不稳定的亲水蛋白质,不具有信号肽和跨膜结构域,可能存在于细胞质、细胞核或过氧化物酶体中,主要由α螺旋、无规卷曲、β折叠和β转角组成,含有ACC中心区、生物素羧化酶、生物素羧基载体蛋白质和羧基转移酶4个保守结构域;系统发育树表明,白灵侧耳ACC的氨基酸序列与担子菌中的刺芹侧耳相似度较高;与对照组(pH5.42)相比,pH为6、7、8、9、10、11时,ACC相对表达量显著增加(P<0.05)。

海带PEPC功能区的原核重组表达及功能鉴定

与其他大型海藻一样,海带同样具备无机碳浓缩机制(CCM),以实现高光合作用效率和生产力。胞质磷酸烯醇式丙酮酸羧化酶(phosphoenolpyruvate carboxylase,PEPC)被认为是海带CCM的重要组件,但目前尚没有关于海带胞质PEPC相关研究报道。本研究自海带配子体全长转录组数据库中筛选到一条可能位于细胞质的PEPC编码基因的cDNA全长序列。通过RT-PCR方法验证,获得SjPEPC基因的cDNA全长,为3503 bp,包含2850 bp的完整开放阅读框、50 bp的5'-UTR和603 bp的3'-UTR。SjPEPC编码一个含949个氨基酸残基的蛋白,相对分子质量为104.91 ku,等电点为7.31。多序列比对显示PEPC的功能位点在不同物种中高度保守,系统演化及序列结构分析表明SjPEPC属于细菌型的PEPC。选取编码SjPEPC功能区的核苷酸序列,利用同源重组技术构建了pET32a-SjPEPC原核表达载体,经过诱导和纯化,得到了分子质量大小为86.3 ku的重组蛋白(rSjPEPC),酶活性测定结果显示,rSjPEPC具有催化PEP发生羧化的活性,比活力为(9.37±0.46)U/mg prot。研究表明,PEPC在海带无机碳储存中可能具有重要功能。本研究可为进一步解析海带CCM提供了分子和生物化学证据。