Lane-Serff Harriet, MacGregor Paula, Peacock Lori, Macleod Olivia Js, Kay Christopher, Gibson Wendy, Higgins Matthew K, Carrington Mark
Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.
Elife. 2016 Apr 15;5:e13044. doi: 10.7554/eLife.13044.
The haptoglobin-haemoglobin receptor of the African trypanosome species, Trypanosoma brucei, is expressed when the parasite is in the bloodstream of the mammalian host, allowing it to acquire haem through the uptake of haptoglobin-haemoglobin complexes. Here we show that in Trypanosoma congolense this receptor is instead expressed in the epimastigote developmental stage that occurs in the tsetse fly, where it acts as a haemoglobin receptor. We also present the structure of the T. congolense receptor in complex with haemoglobin. This allows us to propose an evolutionary history for this receptor, charting the structural and cellular changes that took place as it adapted from a role in the insect to a new role in the mammalian host.
非洲锥虫物种布氏锥虫(Trypanosoma brucei)的触珠蛋白-血红蛋白受体,在寄生虫处于哺乳动物宿主的血液中时表达,使其能够通过摄取触珠蛋白-血红蛋白复合物来获取血红素。在这里我们表明,在刚果锥虫(Trypanosoma congolense)中,该受体反而在采采蝇体内发生的上鞭毛体发育阶段表达,在那里它作为血红蛋白受体发挥作用。我们还展示了与血红蛋白结合的刚果锥虫受体的结构。这使我们能够提出该受体的进化史,描绘出它从在昆虫中的作用适应到在哺乳动物宿主中的新作用时发生的结构和细胞变化。