Voss T, Eistetter H, Schäfer K P, Engel J
Abteilung für Molekularbiologie, Byk Gulden Pharmazeutika, Konstanz, FRG.
J Mol Biol. 1988 May 5;201(1):219-27. doi: 10.1016/0022-2836(88)90448-2.
The macromolecular structure of the pulmonary surfactant apolipoprotein SP 28-36 has been determined. For SP 28-36 isolated from dog lung lavage, a flower bouquet-like hexameric structure with six globular domains connected by short stalks to a common stem was revealed by electron microscopy, using the rotary shadowing technique. This structure is very similar to that published for the subcomponent C1q of the first component of complement C1. The lavage material was compared with the homologous human recombinant SP 28-36 by the same technique. Mostly smaller aggregates like di-, tri- and tetramers as well as very high aggregates were observed. Mild reduction of the recombinant material revealed the lollipop-shaped monomers composed of a globular domain and a tail with a discrete kink in the middle portion. The collagenous nature of the tail was demonstrated by circular dichroism spectroscopy. This implies that the mammalian expression system assembles the monomeric subunits correctly. Assembly into the hexameric structures, however, does not proceed quantitatively.
肺表面活性物质载脂蛋白SP 28 - 36的大分子结构已被确定。对于从犬肺灌洗物中分离出的SP 28 - 36，使用旋转阴影技术通过电子显微镜揭示了一种花束状的六聚体结构，该结构有六个球状结构域通过短茎连接到一个共同的茎上。这种结构与已发表的补体C1第一成分的亚成分C1q的结构非常相似。通过相同技术将灌洗物材料与同源的人重组SP 28 - 36进行比较。观察到的大多是较小的聚集体，如二聚体、三聚体和四聚体以及非常大的聚集体。对重组材料进行温和还原后，发现了由球状结构域和在中间部分有一个离散扭结的尾巴组成的棒棒糖状单体。通过圆二色光谱法证明了尾巴的胶原性质。这意味着哺乳动物表达系统正确地组装了单体亚基。然而，组装成六聚体结构并没有定量进行。
