Verdaguer N, Perelló M, Palau J, Subirana J A
Departament d'Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya, Barcelona, Spain.
Eur J Biochem. 1993 Jun 15;214(3):879-87. doi: 10.1111/j.1432-1033.1993.tb17991.x.
We describe structural studies carried out with some basic proteins found in association with DNA in the spermatozoa of molluscs and echinoderms. We have studied proteins related to histone H1 as well as protamines. Structural prediction methods show that these proteins have a strong helical potential and contain several turns, mainly of the SPKK type. No beta structures were found. Strong structural similarities have been detected between distantly related species. The presence of helical regions is confirmed by circular dichroism in trifluoroethanol solution. The influence of the SPKK turns is also evident in the CD spectra. In proteins which contain a high percentage of arginine we conclude that conventional prediction methods should be modified in order to allow for a higher helical potential for this amino acid residue. Synthetic peptides with a sequence present in the C-terminal region of histone H1 have also been studied. It was found that octapeptides may only acquire a small amount of structure, whereas hexadecapeptides are 50-60% helical. These studies strongly suggest that both protamines and proteins related to the C-terminal part of histone H1 interact with DNA mainly in the alpha-helical conformation.
我们描述了对软体动物和棘皮动物精子中与DNA相关的一些碱性蛋白质所进行的结构研究。我们研究了与组蛋白H1以及鱼精蛋白相关的蛋白质。结构预测方法表明，这些蛋白质具有很强的螺旋潜力，包含几个螺旋圈，主要是SPKK类型。未发现β结构。在远缘物种之间检测到了很强的结构相似性。三氟乙醇溶液中的圆二色性证实了螺旋区域的存在。SPKK螺旋圈在圆二色光谱中也很明显。对于含有高比例精氨酸的蛋白质，我们得出结论，应修改传统的预测方法，以便考虑到该氨基酸残基更高的螺旋潜力。还研究了具有组蛋白H1 C端区域序列的合成肽。发现八肽可能只获得少量结构，而十六肽有50 - 60%呈螺旋状。这些研究强烈表明，鱼精蛋白和与组蛋白H1 C端部分相关的蛋白质主要以α螺旋构象与DNA相互作用。
