Haagsman H P, Hawgood S, Sargeant T, Buckley D, White R T, Drickamer K, Benson B J
Cardiovascular Research Institute, University of California, San Francisco 94143.
J Biol Chem. 1987 Oct 15;262(29):13877-80.
SP 28-36, a major protein of pulmonary surfactant, has striking amino acid sequence homology with soluble mannose-binding proteins isolated from rat liver and contains residues common to the carbohydrate-binding domains of other mammalian lectins. We have used carbohydrate-affinity chromatography to investigate carbohydrate-binding properties of SP 28-36 isolated from canine and human (alveolar proteinosis patients) lung lavage. SP 28-36 binds to immobilized D-mannose, L-fucose, D-galactose, and D-glucose. The protein binds only weakly to N-acetyl-D-galactosamine and N acetyl-D-glucosamine. Binding is Ca2+-dependent. The threshold Ca2+ concentration is 0.6 mM and maximal binding occurs with 1 mM Ca2+. Bound protein is quantitatively recovered by elution with 2 mM EDTA. Ba2+, Sr2+, and Mn2+, but not Mg2+, can substitute for Ca2+. Unlike some other mammalian lectins, SP 28-36 binds to carbohydrate at pH 5.0. Recombinant human SP 28-36 isolated from the media of Chinese hamster ovary cells, transfected with a DNA construct encoding SP 28-36, has similar carbohydrate-binding activity to the native proteins. Mannose affinity chromatography of the culture medium of Chinese hamster ovary cells results in an efficient purification of the secreted recombinant human SP 28-36.
表面活性蛋白28 - 36（SP 28 - 36）是肺表面活性剂的一种主要蛋白质，与从大鼠肝脏分离出的可溶性甘露糖结合蛋白具有显著的氨基酸序列同源性，并且含有其他哺乳动物凝集素碳水化合物结合结构域的共同残基。我们利用碳水化合物亲和层析法研究了从犬类和人类（肺泡蛋白沉积症患者）肺灌洗物中分离出的SP 28 - 36的碳水化合物结合特性。SP 28 - 36能与固定化的D - 甘露糖、L - 岩藻糖、D - 半乳糖和D - 葡萄糖结合。该蛋白与N - 乙酰 - D - 半乳糖胺和N - 乙酰 - D - 葡糖胺的结合较弱。结合是钙离子依赖性的。钙离子的阈值浓度为0.6 mM，最大结合发生在1 mM钙离子时。通过用2 mM乙二胺四乙酸（EDTA）洗脱可定量回收结合的蛋白。钡离子、锶离子和锰离子可替代钙离子，但镁离子不能。与其他一些哺乳动物凝集素不同，SP 28 - 36在pH 5.0时能与碳水化合物结合。从转染了编码SP 28 - 36的DNA构建体的中国仓鼠卵巢细胞培养基中分离出的重组人SP 28 - 36，具有与天然蛋白相似的碳水化合物结合活性。对中国仓鼠卵巢细胞培养基进行甘露糖亲和层析可有效纯化分泌的重组人SP 28 - 36。
