Pancer Z, Leuck J, Rinkevich B, Steffen R, Müller I, Müller W E
Abteilung für Angewandte Molekularbiologie, Universität, Mainz, Germany.
Mol Mar Biol Biotechnol. 1996 Dec;5(4):326-33.
Botryllus schlosseri is a colonial marine invertebrate that belongs to the subphylum Urochordata. Previously we analyzed the activity of a serine protease in this species, and cloned a tunicate chymotrypsin-like molecule. In the present study we further analyzed the protease activity of this animal, and found biochemical evidence also for specific trypsin-like activity. Subsequently we utilized a degenerate polymerase chain reaction (PCR) primer to clone two B. schlosseri cDNAs coding for two different putative trypsinogens, each 243 amino acids long, that differ within the coding region in 42 amino acids and 99 nucleotides. Both clones feature the characteristics of animal anionic trypsinogens. Sequence analysis of the tunicate putative trypsinogens revealed the invertebrate characteristics of three disulfide bridges, and higher similarity to invertebrate than to vertebrate trypsinogens. We therefore propose that the typical characteristics of vertebrate trypsinogens evolved after the divergence of Urochordates and Cephalochordates.
柄海鞘是一种群体海洋无脊椎动物，属于尾索动物亚门。此前我们分析了该物种中一种丝氨酸蛋白酶的活性，并克隆了一种类似胰凝乳蛋白酶的被囊动物分子。在本研究中，我们进一步分析了这种动物的蛋白酶活性，并发现了特定胰蛋白酶样活性的生化证据。随后，我们利用简并聚合酶链反应（PCR）引物克隆了两个柄海鞘cDNA，它们编码两种不同的假定胰蛋白酶原，每种长度为243个氨基酸，在编码区域内有42个氨基酸和99个核苷酸不同。两个克隆都具有动物阴离子胰蛋白酶原的特征。对被囊动物假定胰蛋白酶原的序列分析揭示了三个二硫键的无脊椎动物特征，并且与无脊椎动物胰蛋白酶原的相似性高于与脊椎动物胰蛋白酶原的相似性。因此，我们提出脊椎动物胰蛋白酶原的典型特征是在尾索动物和头索动物分化之后进化而来的。
