CAJ | 학술논문

黄精凝集素Ⅱ(Polygonatum cyrtonema Hua．LectinⅡ，PCLⅡ)具有323nm的荧光发射峰和281．6nm的激发峰．其远紫外圆二色谱(CD谱)显示224nm负峰，分子中含17．3％的α螺旋和45．8％的β折叠．在10mmol/L的SDS中，PCLⅡ完全丧失兔红细胞凝集能力及促T-淋巴细胞有丝分裂活性，CD谱呈现双负峰的α螺旋构象；去除SDS后，则呈无规卷曲构象．此时，荧光发射峰红移而激发峰蓝移，PCLⅡ仍完全失活．在EDTANa2溶液中，PCLⅡ凝集红细胞能力及促淋巴细胞有丝分裂活性完全丧失；去除EDTA后，红细胞凝集活性完全恢复，但仍失去促淋巴细胞有丝分裂能力．PCLⅡ二级结构变化不大，荧光光谱的变化表明微环境受到影响．
황정응집소Ⅱ(Polygonatum cyrtonema Hua．LectinⅡ，PCLⅡ)구유323nm적형광발사봉화281．6nm적격발봉．기원자외원이색보(CD보)현시224nm부봉，분자중함17．3％적α라선화45．8％적β절첩．재10mmol/L적SDS중，PCLⅡ완전상실토홍세포응집능력급촉T-림파세포유사분렬활성，CD보정현쌍부봉적α라선구상；거제SDS후，칙정무규권곡구상．차시，형광발사봉홍이이격발봉람이，PCLⅡ잉완전실활．재EDTANa2용액중，PCLⅡ응집홍세포능력급촉림파세포유사분렬활성완전상실；거제EDTA후，홍세포응집활성완전회복，단잉실거촉림파세포유사분렬능력．PCLⅡ이급결구변화불대，형광광보적변화표명미배경수도영향．
To demonstrate the roles of Ca2+、 Mg2+ in the conformation and function of Polygonatum cyrtonema Hua. lectin Ⅱ (abbev. PCLⅡ), the conformational changeof PCL Ⅱ was studied by fluorescence and circular dichroism (CD) spectra. Intrinsic fluorescence of PCL Ⅱ showed the λmax of emission and excitation spectrum at 323nm and 281.6nm respectively, it indicared that tryptophan was in a hydrophobic microenvironment. The relative fluorescence intensity excitated at 281.6nm was bigger than that at 295nm so far, so the energy was transfered from tyrosin to tryptophan. The far ultraviolet (UV) CD spectra exhibited a rare negative peak with minimum at 224nm and two negative shoulders at 212nm and 234nm, While its near-UV CD spectra showed negative peak at 278nm and shoulders at 260nm、285nm、 300nm. It contains about 17.3% α-helix and 45.8% β-sheet. In 10mmol/L sodium dodecyl sulphate(SDS), the near-UV CD spectra disappeared, while far-UV CD spectra showed a typical double negative peaks between 200～225nm, removed with excess SDS, the near-UV spectra centered at 278m regained partly, but at far-UV region, it exhibited a random coil curve. The λmax of fluo-rescence emission spectra red-shifted to 331nm. but excitation spectra blue-shifted to 279nm, the relative fluorescence intensity all increased about 70 %, PCL Ⅱ lost activity as hemagglutination and mitogen towards T-cell completely. Treated with disodium ethylene diamine tetracetate(EDTANa2), PCLⅡ lost activity as mentioned, the negative shoulder at 212nm disappeared, while the peak and shoulder of near-UV region at 278nm and 300nm red-shifted, and a new shoulder appeared at 275nm. Removing EDTANa2, the new shoulder at 275m disappeared, λmax of emission and excitation spectra were all blue-shifted with the increased relative fluorescence intensity, PCL Ⅱ left hemagglutination activity intact, but lost mitogenic activity towards T-cell, so at least there were two functional domain in PCL Ⅱ to start various reaction, EDTANa2 could inhibite the hemagglutination of PCL Ⅱ. Maybe Ca2+ , Mg2+ were need for PCL Ⅱ to maintain special microenvironment conformation to trigger serial signal and result the division of T-cell, but not essential for hemagglutination.