CJCU

Chem. J. Chinese Universities ›› 2009, Vol. 30 ›› Issue (9): 1773.

• Articles • Previous Articles     Next Articles

Effect of Metal Ions on the Biological Activity and Structural Information of Snake Venom Proteins

LIU Shu-Qing1*, GUO Chun-Mei1,2, XU Yue-Fei1, SUN Ming-Zhong2*, XIN Yi2, TANG Jian-Wu3   

  1. 1. Department of Biochemistry and Molecular Biology,
    2. Department of Biotechnology, College of Basic Medical Science,
    3. Department of Pathology, Dalian Medical University, Dalian 116044, China
  • Received:2009-01-09 Online:2009-09-10 Published:2009-09-10
  • Contact: LIU Shu-Qing. E-mail: mxs288@gmail.com; SUN Ming-Zhong. E-mail: lsqsmz@gmail.com
  • Supported by:

    国家自然科学基金(批准号: 30572098, 30772468)和大连市科技厅项目(批准号: 2008J22JH014)资助.

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Abstract:

Three bioactive proteins of the snake venom of Gloydius blomhoffii brevicaudus(GBB) were for the first time purified to be homogenous, as determined by both SDS-PAGE and mass spectrometry. HPLC-nESI-MS/MS approach was carried out to get the amino acid sequences of the tryptic-digested peptides. On the basis of the sequencing comparisons of the three proteins with other known snake venom protein homologue, those proteins are identified as three novel basic phospholipase A2(bPLA2), metalloproteinase(MP) and thrombin-like enzyme(TLE), which are named as GBB-bPLA2, GBB-MP and GBB-TLE, respectively. Results from inductively coupled plasma atomic emission spectrometry(ICP-AES) indicate that GBB-bPLA2 and GBB-MP are Ca2+ containing proteins with the calcium stoichiometry of 1∶1([Ca2+]/[protein]), and GBB-TLE is a Zn2+ protein with a molar ratio of 2∶1([Zn2+]/[protein]). Ca2+ is critical for the enzymatic activities of GBB-bPLA2 and GBB-MP. Ca2+ ion induced 2.0 nm blue-shift and 1.6 nm blue-shift for the intrinsic fluorescences of GBB-bPLA2 and GBB-MP, respectively. The existence of Ca2+ also increased the maximum emission fluorescence intensities of GBB-bPLA2 and GBB-MP by 14.0% and 11.0%, respectively. Ca2+ could raise the denaturing temperature of GBB-bPLA2 and GBB-MP by 1.5 and 2.0 ℃, which resulted in higher thermal stabilities for them. Zn2+ ion could enhance the fluorescence intensity of GBB-TLE by 4.3%, however it did not show apparent influence on its esterase hydrolytic activity. Zn2+ only showed slight effect on the emission fluorescence wavelength and thermal stability of GBB-TLE. The existence of metal ions apparently affects the structure-related thermal stabilities of the metal-containing proteins of snake venom to different extents, meanwhile, the metal ions exhibit diverse influences on their enzymatic activities.

Key words: Snake venom protein; Metal ion; Activity

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