Molecular properties of a hemagglutinin purified from type A Clostridium botulinum.
Molecular properties of a hemagglutinin purified from type A Clostridium botulinum.
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从 A 型肉毒梭菌纯化的血凝素的分子特性。
DOI：
10.1023/a:1020691215056
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Singh,BR
中科院分区：
文献类型：
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作者：
Sharma,SK;Fu,FN;Singh,BR
肉毒杆菌通过产生肉毒杆菌神经毒素（已知最有效的毒素）而引起食物中毒疾病肉毒杆菌中毒。神经毒素与一组神经毒素相关蛋白（NAP）一起产生，可以保护其免受胃肠道低 pH 值和蛋白酶的影响。最近，我们分离出了 NAP 的主要成分之一，即 33 kDa 血凝素 (Hn-33) [Fuet al.(1998),J.蛋白质化学 17, 53–60]。在这项研究中，我们展示了源自多种生化和生物物理技术的 Hn-33 的分子特性。纯形式的 Hn-33 需要比其与神经毒素和其他 NAP 复合形式低 66 倍的糖浓度来抑制其血凝活性。然而，其蛋白酶抗性不受糖结合的影响。根据 FT-IR 和圆二色性 (CD) 分析，Hn-33 是一种主要为 β 片层的蛋白 (74–77%)。通过激光解吸质谱和尺寸排阻柱色谱法对 Hn-33 进行分析表明，它在水溶液中主要以二聚体形式存在。远紫外 CD 分析显示，即使是非常低浓度的 SDS (0.05%)，也会通过改变其二级结构来不可逆地破坏 Hn-33 的生物活性。
Clostridium botulinumcauses the food poisoning disease botulism by producing botulinum neurotoxin, the most potent toxin known. The neurotoxin is produced along with a group of neurotoxin-associated proteins, or NAPs, which protect it from the low pH and proteases of the gastrointestinal tract. Recently, we isolated one of the major components of NAPs, a 33-kDa hemagglutinin (Hn-33) [Fuet al.(1998),J. Protein Chem.17, 53–60]. In this study, we present molecular properties of Hn-33 derived from several biochemical and biophysical techniques. Hn-33 in pure form requires a 66-fold lower concentration of sugar inhibition of its hemagglutination activity than in its complexed form with the neurotoxin and other NAPs. However, its protease resistance is not affected by sugar binding. Based on FT-IR and circular dichroism (CD) analysis, Hn-33 is a predominantly β-sheet protein (74–77%). Hn-33 analysis by laser desorption mass spectrometry and size exclusion column chromatography reveals that it exists predominantly in a dimeric form in the aqueous solution. Even a very low concentration of SDS (0.05%) irreversibly destroyed the biological activity of Hn-33 by changing its secondary structure as revealed by far-UV CD analysis.