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用远紫外CD谱研究了皖南尖吻蝮蛇蛇毒3个出血毒素AaHⅠ、AaHⅢ和AaHⅣ的溶液构象,AaHⅠ的α螺旋、β折叠、β转角和无规卷曲的含量分别为25.8%、12.7%、26.8%和34.7%;AaHⅢ的二级结构含量分别为23.9%、20.6%、23.7%和31.8%;而AaHⅣ分别为18.2%、31.0%、17.2%和33.6%。当pH小于4.0或pH大于11.0时,3种出血毒素α螺旋减少而β折叠增多,同时3种出血毒素的酪蛋白水解活性显著下降。EDTA抑制酪蛋白水解活性,表明3种出血毒素均是金属蛋白酶。EDTA、Cu2+、Zn2+、Ca2+和Mg2+能改变3种出血毒素的二级结构,并影响酪蛋白水解活性。
The solution conformations of three hemorrhagic toxins AaHⅠ, AaHⅢ and AaHⅣ in southern Anhui snake venom were studied by far-UV CD spectra. The content of α-helix, β-sheet, β-turn and random coils of AaHⅠwas 25.8%, 12 .7%, 26.8% and 34.7% respectively. The secondary structure contents of AaHⅢ were 23.9%, 20.6%, 23.7% and 31.8% , 31.0%, 17.2% and 33.6% respectively. When the pH was less than 4.0 or the pH was greater than 11.0, the three hemorrhagic toxin alpha helix decreased and beta sheet increased, while the casein hydrolytic activity of the three hemorrhagic toxins was significantly decreased. EDTA inhibited casein proteolytic activity, indicating that all 3 hemolysins are metalloproteases. EDTA, Cu2 +, Zn2 +, Ca2 + and Mg2 + can change the secondary structure of three hemorrhagic toxins and affect casein proteolytic activity.