梯棱羊肚菌凝集素MIL的外源表达及生物活性

对梯棱羊肚菌(Morchella importuna)凝集素编码基因MIL及其编码蛋白进行生物信息学分析,并采用qRT-PCR分析MIL基因在梯棱羊肚菌不同生长发育阶段(菌丝期、白色菌核期、黄色菌核期、原基期、幼菇期、成熟子囊果期)的表达量;构建pET28a-MIL表达载体,在大肠杆菌(Escherichia coli)BL21中外源表达获得了凝集素蛋白MIL-His,测定其生物活性。研究表明,梯棱羊肚菌MIL基因序列为426 bp,其中含有一个RicinB lectin保守结构域,与RicinB-like lectin同源性达95%;qRT-PCR定量分析显示,在从菌丝到子囊果的生长发育过程中,梯棱羊肚菌MIL基因在白色菌核阶段的表达量最高,其次为黄色菌核阶段,幼菇、成熟子囊果和原基阶段次之,在菌丝阶段表达量最低,表明MIL基因可能在梯棱羊肚菌菌核形成中起到重要的调控作用;兔红细胞凝血实验结果显示重组蛋白MIL-His凝集兔红细胞的最小浓度为0.32 mg/mL,同时发现MIL-His具有提高小鼠脾脏淋巴细胞增殖率的活性,与对照相比增殖率达35.3%。

一种新杨树菇(Agrocybe aegerita)凝集素的纯化及生化特性

用硫酸铵分级沉淀、离子交换和分子筛等方法 ,从食用菌杨树菇子实体中分离纯化了一种凝集素 ,称作为AAVP(Agrocybeaegeritaantiviralprotein) .经SDS PAGE测定其亚基的相对分子质量为15 8kD ,凝胶过滤分析分子量为 32kD .IEF PAGE计算其等电点为 3 8.AAVP不含糖 ,是一种N端焦谷氨酰环化封闭的蛋白质 ,经N端去封闭后测得N端氨基酸序列为QGVNIYNIVAGA ,用胰蛋白酶消化后得到一大片段 ,测定的氨基酸序列为PDGPWLVEK .AAVP可以凝集供试的 12种动物血和3种血型人血的血红细胞 ,但对各种血红细胞凝集滴度不同 .糖抑制实验表明 ,在供试的 18种单糖和 3种糖蛋白中 ,只有猪胃粘蛋白强烈抑制AAVP的凝血活性 .AAVP具有较好的热稳定性 ,能够忍受极端的酸碱条件 .AAVP的凝血活性不受Ca2 + 、Mg2 + 、Zn2 + 等二价阳离子的影响 .抗肿瘤活性检测表明 ,AAVP对胃癌细胞株SGC 790 1,MGC 80 3,BGC82 3及人急性白血病细胞株HL 6 0有明显的抑制作用 .AAVP对小鼠腹腔注射的半致死剂量为 15 85mg kg .

长白山药用真菌树舌凝集素的纯化及生化特性

用硫酸铵分级沉淀、离子交换和HPLC层析等方法,从长白山药用真菌树舌的菌丝体中分离纯化了一种凝集素(Ganoderma applanatum lectin,简称GAL),SDS-PAGE检测其为单一蛋白条带。经过SDS-PAGE测得其亚基分子量为15kDa左右,HPLC分析分子量为58kDa左右,表明GAL由4个亚基组成。氨基酸组成分析表明,GAL中甘氨酸含量较高,不含蛋氨酸和色氨酸,中性糖含量约11.2%。圆二色CD谱显示其含有3.6%的α螺旋、46.8%的β转角和49.6%无规则卷曲,不含有β折叠。GAL可以凝集供试的2种动物血和3种血型人血的血红细胞,但对不同来源的血红细胞凝集滴度不同。糖抑制实验表明,只有棉籽糖和D-松三糖部分抑制GAL的凝血活性。GAL具有较好的热稳定性且其凝血活性不受Ca2+、Mg2+和Zn2+等二价阳离子的影响。

一种新的蘑菇凝集素的生化特征和氨基酸分析

用 (NH4) 2 SO4分级沉淀、离子交换和分子筛等方法 ,从食用蘑菇中分离纯化出一种凝集素 ,经SDS -PAGE测定其亚基的相对分子量为 15 .8kDa,质谱分析法测定其分子量为 32kDa ,说明该凝集素由两个亚基组成。氨基酸分析发现 ,该凝集素不含半胱氨酸。热稳定试验和耐酸碱试验显示 。

桑黄发酵液中凝集素SHL24的分离与生物活性研究

【背景】桑黄是一种具有很高药用价值及广泛应用前景的药用真菌,其主要有效成分为多糖。凝集素则是桑黄所含的另一类生物活性物质,具有免疫调节、抗肿瘤及抗菌等作用。【目的】从药用真菌桑黄发酵液中分离纯化凝集素SHL24,并对其生物活性进行初步探究。【方法】通过冷冻干燥、Sephadex G-50、DEAE Sephadex A-25、MPLC-MonoQ和LPLC-Sephadex G-75等方法,从药用真菌桑黄的发酵液中进行分离纯化;利用LPLC-Sephadex G-75和SDS-PAGE凝胶电泳鉴定其分子质量;检测不同pH、金属离子、糖、发酵时间、血红细胞、温度对其凝血活性的影响。【结果】从药用真菌桑黄发酵液中分离到单一蛋白条带,SDS-PAGE凝胶电泳检测其分子质量约为24 kD,与分子筛层析法分析的分子质量一致,表明该凝集素为单亚基蛋白。SHL24可以凝集供试的小鼠血红细胞和4种血型人血的血红细胞,但对不同来源的血红细胞凝集程度不同。糖抑制试验表明,SHL24不被D-甘露糖、D-麦芽糖、葡萄糖、蔗糖、树胶醛糖、D-乳糖以及L-鼠李糖所抑制。热稳定性试验和金属离子对SHL24凝血活性影响试验表明SHL24具有较好的热稳定性且其凝血活性不受Ca^(2+)、Mg^(2+)和Zn^(2+)等二价阳离子的影响。【结论】SHL24具有的稳定理化性质和生物活性,有作为蛋白质药物的潜质。

Research on the Lectin in Muscle Tissue of Varicorhinus macrolepis

[Objective] The paper aimed at researching lectins in muscles of Varicorhinus macrolepis and providing scientific basis for researching the adaptation mechanism and immune response of V.macrolepis to environment,which were advantageous for the protection and reproduction of V.macrolepis.[Method] V.macrolepis was used as test materials for the hemagglutination test by dialdehyde fixation to prove the existence of lectins in muscle crude homogenate of Varicorhinus macrolepis and study the physical and chemical characters.[Result] Lectins in muscle crude homogenate of V.macrolepis had shown hemagglutination effects on erythrocytes of six types of animals and had the maximum hemagglutination activity against rabbit erythrocytes,which belonged to the S-type lectins with optimal pH ranged from 4 to 8 and optimal temperature at 60 ℃.Results from the saccharide inhibition test had indicated that the sucrose was the only kind of saccharide which had inhibited the hemagglutination,suggesting that sucrose had played an important role in the process of recognition and aggregation of lectins.[Conclusion] It had been speculated that the optimal pH ranges for thermal sensitivity and hemagglutination activity of lectins in different types of aquatic organisms were similar.

Biological Characteristics of Serum Agglutinin from Portunus trituberculatus

The agglutination characteristics of serum agglutinin from Portunus trituberculatus were studied in this paper. The results showed that the serum agglutinin had no agglutination to crucian carp, Chinese soft shell turtle, grass carp, chicken or human group A, B or O blood cells, but had strong agglutination to blood cells of mice and rabbits. The activities of serum agglutinin from Portunus trituberculatus to mice blood cells reached 210, and to rabbit blood cells reached 28. Salinity had a greater effect on agglutinin activity. When the Na Cl concentration exceeded 0.6 mol/L,the serum agglutinin from Portunus trituberculatus was basically inactivated. The optimum p H for agglutinin activity was 6.0-7.4. The serum agglutinin from Portunus trituberculatus had obvious dependence to Ca2 ＋and Mg2 ＋, and EDTA could significantly inhibit its activity. The results of sugar inhibition test showed that the activity of agglutinin from Portunus trituberculatus can be specifically inhibited by N-acetylglucosamine and N-acetylmannosamine. The serum agglutinin from Portunus trituberculatus was isolated by ammonium sulfate gradient precipitation, and its activity was highest by the 25% ammonium sulfate precipitation system. The SDS polyacrylamide gel electrophoresis（SDS-PAGE） showed that the protein bands were mainly distributed within 72-95 ku.