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题名: Structural and Functional Comparisons and Production of Recombinant Crustacean Hyperglycemic Hormone (CHH) and CHH-like Peptides from the Mud Crab Scylla Olivacea
作者: Chang, Chih-Chun;Tsai, Kuo-Wei;Hsiao, Nai-Wan;Chang, Cheng-Yen;Lin, Chih-Lung;Watson, R. Douglas;Lee, Chi-Ying
贡献者: 生物學系
关键词: Crustacean hyperglycemic hormone;Crustacean hyperglycemic hormone-like peptide;Recombinant proteins;Circular dichroism;Melting temperature;Biological activity;Comparative modeling
日期: 2010-05
上传时间: 2012-07-03T04:03:00Z
出版者: Elsevier
摘要: Sco-CHH and Sco-CHH-L (CHH-like peptide), two structural variants of the crustacean hyperglycemic hormone family identified in the mud crab (Scylla olivacea), are presumably alternatively spliced gene products. In this study, Sco-CHH and Sco-CHH-L were isolated from the tissues using high performance liquid chromatography. Identity of the native peptides was confirmed using mass spectrometric (MS) analyses of purified materials and of trypsin-digested peptide fragments. Additionally, characterizations using circular dichroism (CD) spectrometry revealed that the 2 peptides have similar CD spectral profiles, showing they are composed mainly of α-helices, and are similarly thermo-stable with a melting temperature of 74–75 °C. Results of bioassays indicated that Sco-CHH exerted hyperglycemic and molt-inhibiting activity, whereas Sco-CHH-L did not. Further, recombinant Sco-CHH-Gly (rSco-CHH-Gly, a glycine extended Sco-CHH) and Sco-CHH-L (rSco-CHH-L) were produced using an Escherichia coli expression system, refolded, and purified. rSco-CHH-Gly was further α-amidated at the C-terminal end to produce rSco-CHH. MS analyses of enzyme-digested peptide fragments of rSco-CHH-Gly and rSco-CHH-L showed that the two peptides share a common disulfide bond pattern: C7-C43, C23-C39, and C26-C52. Circular dichroism analyses and hyperglycemic assay revealed that rSco-CHH and rSco-CHH-L resemble their native counterparts, in terms of CD spectral profiles, melting curve profiles, and biological activity. rSco-CHH-Gly has a lower α-helical content (32%) than rSco-CHH (47%), a structural deviation that may be responsible for the significant decrease in the biological activity of rSco-CHH-Gly. Finally, modeled structure of Sco-CHH and Sco-CHH-L indicated that they are similarly folded, each with an N-terminal tail region and 4 α-helices. Putative surface residues located in corresponding positions of Sco-CHH and Sco-CHH-L but with side chains of different properties were identified. The combined results support the notion that Sco-CHH and Sco-CHH-L are functionally different, but resemble each other at higher-level structures. Functional diversity between the 2 peptides is probably due to critical residues located in the C-terminus. The availability of large amounts of recombinant proteins will permit additional functional and structural studies of these CHH family peptides.
關聯: General and Comparative Endocrinology, 167(1): 68-76
显示于类别:[生物學系] 期刊論文

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