CAJ | 학술논문

细菌锌吸收调控蛋白(Zur)在调控细胞锌离子平衡中起核心作用。研究发现，大肠杆菌的Zur蛋白(ZurE. coli)中半胱氨酸残基Cys93、Cys96、Cys143和Cys146是锌离子结合位点，是感受锌离子浓度和调控锌离子平衡必需的氨基酸残基。本文研究了十字花科黒腐病菌(Xanthomonas campestris pathovar campestris,简称Xcc)的Zur蛋白(ZurXcc)。序列分析结果显示，ZurXcc的Cys125、Cys128、Cys165和Cys168是与ZurE. coli的Cys93、Cys96、Cys143和Cys146相对应的半胱氨酸残基，预示它们可能是ZurXcc中的锌离子结合位点。此外，氨基酸置换结果发现， Cys125、Cys128、Cys165和Cys168中任何一个被其它氨基酸置换后，ZurXcc即丧失调控锌离子平衡的能力，证明它们是ZurXcc调控锌离子平衡必不可少的，是可能的锌离子结合位点。胞外多糖(EPS)产量和致病力检测结果还表明，ZurXcc调控锌离子平衡、EPS产生和调控致病在结构和功能上都是可以分开的。
세균자흡수조공단백(Zur)재조공세포자리자평형중기핵심작용。연구발현，대장간균적Zur단백(ZurE. coli)중반광안산잔기Cys93、Cys96、Cys143화Cys146시자리자결합위점，시감수자리자농도화조공자리자평형필수적안기산잔기。본문연구료십자화과흑부병균(Xanthomonas campestris pathovar campestris,간칭Xcc)적Zur단백(ZurXcc)。서렬분석결과현시，ZurXcc적Cys125、Cys128、Cys165화Cys168시여ZurE. coli적Cys93、Cys96、Cys143화Cys146상대응적반광안산잔기，예시타문가능시ZurXcc중적자리자결합위점。차외，안기산치환결과발현， Cys125、Cys128、Cys165화Cys168중임하일개피기타안기산치환후，ZurXcc즉상실조공자리자평형적능력，증명타문시ZurXcc조공자리자평형필불가소적，시가능적자리자결합위점。포외다당(EPS)산량화치병력검측결과환표명，ZurXcc조공자리자평형、EPS산생화조공치병재결구화공능상도시가이분개적。
Bacteria zinc uptake regulator, Zur, plays a central role in zinc homeostasis. It has been known that the cysteine residues at positions of 93rd, 96th, 143rd, and 146th in E. coli (ZurE. coli) are the Zn2+-binding sites and thus are es-sential for the Zn2+sensing and zinc homeostasis regulation of ZurE. coli. Here, we investigate the Zur of Xanthomonas campestris pathovar campestris (Xcc) (ZurXcc). Amino acid sequence analysis reveal that Cys125, Cys128, Cys165 and Cys168 in ZurXcc are corresponding to Cys93, Cys96, Cys143 and Cys146 of ZurE. coli respectively, suggesting that these residues may involve in binding of Zn2+. To challenge this hypothesis, the contribution of each of the four cysteine residues to Zur function was determined using amino acid substitution analysis. The results show that, amino acid substitution in Cys125, Cys128, Cys165 and Cys168 resulted in lost of the zinc homeostasis regulating function of ZurXcc, demonstrating that the four cysteine residues are essential for zinc homeostasis regulation of ZurXcc. More important-ly, our results demonstrated that the role of ZurXcc in the regulation of zinc homeostasis, EPS production and viru-lence of Xcc is structurally and functionally separable.