Lee Wen-Hui, Liu Shu-Bai, Shen Ji-Hong, Jin Yang, Lai Ren, Zhang Yun
Department of Animal Toxinology, Kunming Institute of Zoology, The Chinese Academy of Sciences, 32 East Jiao Chang Road, Kunming 650223, Yunnan, China.
Regul Pept. 2005 Jul 15;129(1-3):43-7. doi: 10.1016/j.regpep.2005.01.007.
Amphibian skin contains rich neuropeptides. In the present study, a novel neuromedin U (NmU) analog was isolated from skin secretions of Chinese red belly toad Bombina maxima. Being 17-amino acids long, its primary structure was established as DSSGIVGRPFFLFRPRN-NH2, in which the C-terminal 8-residue segment (FFLFRPRN) is the same as that of rat NmU, while the N-terminal part DSSGIVGRP shows a great sequence variation compared with those of NmU peptides from different resources. The peptide, named Bm-NmU-17, was found to elicit concentration-dependent contractile effects on smooth muscle of rat uterus horns. The cDNA structure of the peptide, as obtained by a 3'-RACE strategy and subsequently cloning from a skin cDNA library, was found to contain a coding region of 438 nucleotides. The encoded precursor is composed of 145 amino acids with a single copy of Bm-NmU-17 located towards the C-terminus. The sequence of the peptide is preceded by a dibasic site (Lys-Arg) and followed by the sequence of Gly-Arg-Lys, providing the sites of cleavage and releasing of the mature peptide.
两栖动物的皮肤含有丰富的神经肽。在本研究中，从中国大蹼铃蟾（Bombina maxima）的皮肤分泌物中分离出一种新型神经介素U（NmU）类似物。它由17个氨基酸组成，其一级结构确定为DSSGIVGRPFFLFRPRN-NH2，其中C端的8个残基片段（FFLFRPRN）与大鼠NmU相同，而N端部分DSSGIVGRP与来自不同来源的NmU肽相比有很大的序列差异。该肽命名为Bm-NmU-17，被发现对大鼠子宫角平滑肌有浓度依赖性收缩作用。通过3'-RACE策略并随后从皮肤cDNA文库中克隆获得的该肽的cDNA结构，发现其含有一个438个核苷酸的编码区。编码的前体由145个氨基酸组成，单个拷贝的Bm-NmU-17位于C端。该肽的序列前面有一个双碱性位点（Lys-Arg），后面是Gly-Arg-Lys序列，这为成熟肽的切割和释放提供了位点。
