布氏布氏锥虫AnTat 1.1的可变表面糖蛋白：分离条件对二硫键连接的二聚体/单体比例的影响

Variant surface glycoprotein of Trypanosoma brucei brucei AnTat 1.1: influence of the isolation conditions upon the disulfide linked dimer/monomer ratio.

Boutignon F, Huet-Duvillier G, Mendonca-Previato L, Gomes V, Hublart M, Degand P

Unité Inserm No. 16, Lille, France.

Comp Biochem Physiol B. 1990;95(2):281-6. doi: 10.1016/0305-0491(90)90077-7.

Abstract

Using the variant surface glycoprotein (VSG) isolation procedure described by Baltz et al. ([1976] Ann. Immunol. (Inst. Pasteur) 127 C, 761-774) which involves suspension of the trypanosomes in a pH 5.5 buffer, the Antwerpen trypanozoon antigenic type (AnTat) 1.1 VSG is mainly obtained as a disulfide linked dimeric form with a trace amount of a monomeric form. 2. The use of a parasite suspension buffer at pH 7.0 results in a slight decrease of the VSG dimer/monomer ratio. 3. pH 5.5 and 7.0 supernatants of centrifuged parasite suspensions were submitted to kinetic incubations at different temperatures and pH, and we found conditions involving transformation of the AnTat 1.1 VSG dimer into the AnTat 1.1 VSG monomer (shifting the pH 5.5 supernatant to pH 7.0 and incubation at room temperature). 4. This transformation of the AnTat 1.1 VSG dimer into the AnTat 1.1 VSG monomer is activated by the addition of 1 mM reduced glutathione, and is inhibited by the addition of 1 mM oxidized glutathione or 0.1 mM N-ethylmaleimide or cadmium acetate.

摘要

使用Baltz等人（[1976]《巴斯德研究所免疫学年报》127C，761 - 774）描述的可变表面糖蛋白（VSG）分离程序，该程序涉及将锥虫悬浮于pH 5.5缓冲液中，安特卫普锥虫抗原型（AnTat）1.1 VSG主要以二硫键连接的二聚体形式获得，伴有微量的单体形式。2. 使用pH 7.0的寄生虫悬浮缓冲液会导致VSG二聚体/单体比例略有下降。3. 将离心后的寄生虫悬浮液的pH 5.5和7.0上清液在不同温度和pH下进行动力学孵育，我们发现了能使AnTat 1.1 VSG二聚体转化为AnTat 1.1 VSG单体的条件（将pH 5.5上清液调至pH 7.0并在室温下孵育）。4. AnTat 1.1 VSG二聚体向AnTat 1.1 VSG单体的这种转化可通过添加1 mM还原型谷胱甘肽来激活，并可通过添加1 mM氧化型谷胱甘肽、0.1 mM N - 乙基马来酰亚胺或醋酸镉来抑制。