CAJ | 학술논문

水稻类金属硫蛋白(rgMT)的两端是高度保守的半胱氨酸富含区的结构域(CR区),中间是不含半胱氨酸的间隔区,呈典型的三段式结构.本研究分别采用距离几何算法和同源建模相结合的方法对水稻类金属硫蛋白进行三级结构建模.在排列出CR区的所有可能的半胱氨酸-金属硫络合的组合方式,并对每一种组合方式给出一定的限制条件后各生成20个随机构象.根据生成的随机构象是否能形成金属硫络合结构,从900个随机构象中最终选出6个构象(N端4种,C端2种组合)作为可能的结构模型.另一方面,采用GOR方法对间隔区进行了二级结构预测,随后用同源建模法对其建模.将上述建成的三部分模型连接起来后形成rgMT的整体三维构象.结果表明rgMT能像哺乳动物MT蛋白一样,可形成两个独立的、在结构和能量上均没有障碍的金属-硫络合结构.介于所有植物类金属硫蛋白都具有典型的三段式结构,其中的一部分还具有与rgMT相同的半胱氨酸排列方式,所以rgMT三维结构模型的建立对于其他植物类金属硫蛋白的结构研究具有重要的参考价值.
수도류금속류단백(rgMT)적량단시고도보수적반광안산부함구적결구역(CR구),중간시불함반광안산적간격구,정전형적삼단식결구.본연구분별채용거리궤하산법화동원건모상결합적방법대수도류금속류단백진행삼급결구건모.재배렬출CR구적소유가능적반광안산-금속류락합적조합방식,병대매일충조합방식급출일정적한제조건후각생성20개수궤구상.근거생성적수궤구상시부능형성금속류락합결구,종900개수궤구상중최종선출6개구상(N단4충,C단2충조합)작위가능적결구모형.령일방면,채용GOR방법대간격구진행료이급결구예측,수후용동원건모법대기건모.장상술건성적삼부분모형련접기래후형성rgMT적정체삼유구상.결과표명rgMT능상포유동물MT단백일양,가형성량개독립적、재결구화능량상균몰유장애적금속-류락합결구.개우소유식물류금속류단백도구유전형적삼단식결구,기중적일부분환구유여rgMT상동적반광안산배렬방식,소이rgMT삼유결구모형적건립대우기타식물류금속류단백적결구연구구유중요적삼고개치.
Rice metallothionein-like protein (rgMT) shows characteristics of a three-section pattern composed of two highly conserved cysteine rich (CR) domains in the terminals and a spacer without cysteine (cys) residues in the center of the molecule. In this paper, the two CR domains and the spacer region were modeled by the distance geometry and homology methods separately. For the CR domains,twenty random models were generated for each cys combination based on the constraint conditions of CXC (C represents cys, X represents any amino acid other than cys), and CXXC motifs and a metal-sulfur chelating cluster. Four models for the N-terminal and two for C-terminal CR domain containing metal chelating structures formed by different combinations of cys were selected from 900 possible conformations.The GOR method was used to predict the secondary structure of the spacer region and its model was built by the homology method. After three parts of the protein were modeled, they were connected to form a three-dimensional structure model of rgMT. The whole conformation showed that rgMT could form two independent metal-sulfur chelating structures connected by a spacer peptide, without a structural or energy barrier for them to form two independent metal-chelating clusters just as mammalian metallothionein (MT) proteins. As all plant metallothionein-like (MT-L) proteins have the same primary structural characteristic, two CR domains connected by a spacer region, and many have the same cys arrangement pattern as rgMT, the three-dimensional structure model of rgMT will provide an important reference for the structural study of other plant MT-L proteins.