Identifying subunits of ATP synthase TF0·F1 in contact with phospholipid head groups α‐Subunits are labelled selectively by a new photoreactive phospholipid designed for hydrophilic photolabelling

[摘要]

A new phospholipid photolabel was introduced by modifying 1,2-dipalmitoylphosphatidylethanolamine with 4-azidosalicylate to 1,2-dipalmitoyl-sn-glycero-3-phospho-N-(4-azido-2-hydroxybenzoyl)ethanolamine (ASA-PE), which could be radioiodinated easily to ¹²⁵ I-ASA-PE. The ATP synthase TF₀·F₁ of the thermophilic bacterium PS3 was reconstituted with soybean phospholipids forming proteoliposomes with high ATP-³² P_i exchange activity. These proteoliposomes were incubated with ₁₂₅I-ASA-PE to provide its selective incorporation into the outside of the phospholipid bilayer. Upon illumination with ultraviolet light α-subunits of TF₁ were predominantly labelled.

[学科分类] 生物化学/生物物理

[关键词] ATP synthase;Photoreactive phospholipid;Hydrophilic photolabeling;α-Subunit;Membrane surface;(Thermophilic bacterium P53);ASA-PE 1;2-dipalmitoyl-sn-glycero-3 phospho-N-(4-azido-2-hydroxybenzoyl)ethanolamine;125I-ASA-PE 1;2-dipalmitoyl-sn-glycero-3-phospho-N-(4-azido-3-[1251] iodo-2-hydroxybenzoyl)ethanolamine;NBD-PE;N(4-nitro-2;1;3-benzoxadiazolyl)phosphati dylethanolamine