Frank R W, Gennaro R, Schneider K, Przybylski M, Romeo D
European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany.
J Biol Chem. 1990 Nov 5;265(31):18871-4.
Bactenecins are highly cationic polypeptides of the large granules of bovine neutrophils, exerting in vitro a potent antimicrobial activity. Two bactenecins, with an approximate molecular weight of 7000 and 5000, called Bac7 and Bac5, are characterized by a high content of proline (greater than 45%) and arginine (greater than 23%) residues. Their complete amino acid sequences were determined by automated Edman degradation combined, in the case of Bac5, with plasma desorption mass spectrometry. Bac7 comprises 59 residues and includes three tandem repeats of a tetradecamer characterized by several Pro-Arg-Pro triplets spaced by single hydrophobic amino acids. Resolution of the primary structure of Bac5 required fragmentation with N-bromosuccinimide as well as digestion of the obtained C-terminal fragment with carboxypeptidases P and Y directly in the mass spectrometer. Bac5 comprises 42 amino acid residues with a repeated motif of Arg-Pro-Pro triplets also alternating with single apolar residues.
杆菌防御素是牛嗜中性粒细胞大颗粒中的高度阳离子化多肽，在体外具有强大的抗菌活性。两种杆菌防御素，分子量约为7000和5000，分别称为Bac7和Bac5，其特征在于脯氨酸（大于45%）和精氨酸（大于23%）残基的含量很高。它们的完整氨基酸序列通过自动Edman降解测定，对于Bac5，还结合了等离子体解吸质谱法。Bac7由59个残基组成，包括一个十四聚体的三个串联重复序列，其特征是由单个疏水氨基酸隔开的几个Pro-Arg-Pro三联体。Bac5一级结构的解析需要用N-溴代琥珀酰亚胺进行片段化，以及直接在质谱仪中用羧肽酶P和Y消化得到的C末端片段。Bac5由42个氨基酸残基组成，具有Arg-Pro-Pro三联体的重复基序，也与单个非极性残基交替出现。
