Shaping mechanisms of metal specificity in a family of metazoan metallothioneins: evolutionary differentiation of mollusc metallothioneins.
Shaping mechanisms of metal specificity in a family of metazoan metallothioneins: evolutionary differentiation of mollusc metallothioneins.
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DOI：
10.1186/1741-7007-9-4
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发表时间：
2011-01-21
期刊：
影响因子：
5.4
通讯作者：
Dallinger R
中科院分区：
文献类型：
--
作者：
Palacios O;Pagani A;Pérez-Rafael S;Egg M;Höckner M;Brandstätter A;Capdevila M;Atrian S;Dallinger R
金属蛋白如金属硫蛋白（MT）中的金属结合特异性程度对其功能准确性至关重要。与大多数其他动物物种不同，肺类软体动物具有负载Cu+或Cd 2+的同型MT亚型。到目前为止，它们已经作为天然金属-MT络合物从蜗牛组织中获得，其中它们参与与各自同种型结合的金属离子种类的代谢。然而，尚未辨别它们的特定金属占据是否是金属可用性的严格控制的结果，或宿主组织中的同种型表达编程的结果，或确定不同金属离子的配位选择的相应肽的结构差异的结果。在这项研究中，罗马蜗牛（Haplypomatia）铜负载和镉负载的异构体（HpCuMT和HpCdMT）被用作模型分子，以阐明生化和进化机制，允许肺MT实现其同源金属离子的特异性。HpCuMT和HpCdMT在Cd 2+、Zn 2+或Cu 2+存在下重组合成，并通过电喷雾质谱、圆二色谱（CD）和紫外-可见（UV-Vis）分光光度法分析相应的金属络合物。这两种MT异构体只能与其同源金属离子形成独特的、同源的和稳定的络合物（Cd 6-HpCdMT和Cu 12-HpCuMT）。酵母互补试验表明，这两种亚型假定金属特异性的功能，在协议与他们的结合偏好，在异源真核环境。在蜗牛生物中，HpCdMT和HpCuMT的功能性金属特异性是由金属特异性转录编程和细胞特异性表达贡献的。从一些蜗牛物种的MT亚型的序列解析和系统发育分析表明，他们拥有一个非特异性和两个金属特异性MT亚型，其金属特异性是完全通过进化调制的非半胱氨酸氨基酸的位置。罗马蜗牛HpCdMT和HpCuMT亚型，因此可以被视为原型的同种型家庭，真正的金属特异性肺内软体动物。这些异构体的多样性可能已经开始由基因复制，随后的物种形成和选择对保护铜为主的代谢途径从非必需的镉相反的需求。使这些蛋白质具有金属特异性的机制也可能与其他金属蛋白有关。
The degree of metal binding specificity in metalloproteins such as metallothioneins (MTs) can be crucial for their functional accuracy. Unlike most other animal species, pulmonate molluscs possess homometallic MT isoforms loaded with Cu+ or Cd2+. They have, so far, been obtained as native metal-MT complexes from snail tissues, where they are involved in the metabolism of the metal ion species bound to the respective isoform. However, it has not as yet been discerned if their specific metal occupation is the result of a rigid control of metal availability, or isoform expression programming in the hosting tissues or of structural differences of the respective peptides determining the coordinative options for the different metal ions. In this study, the Roman snail (Helix pomatia) Cu-loaded and Cd-loaded isoforms (HpCuMT and HpCdMT) were used as model molecules in order to elucidate the biochemical and evolutionary mechanisms permitting pulmonate MTs to achieve specificity for their cognate metal ion. HpCuMT and HpCdMT were recombinantly synthesized in the presence of Cd2+, Zn2+ or Cu2+ and corresponding metal complexes analysed by electrospray mass spectrometry and circular dichroism (CD) and ultra violet-visible (UV-Vis) spectrophotometry. Both MT isoforms were only able to form unique, homometallic and stable complexes (Cd6-HpCdMT and Cu12-HpCuMT) with their cognate metal ions. Yeast complementation assays demonstrated that the two isoforms assumed metal-specific functions, in agreement with their binding preferences, in heterologous eukaryotic environments. In the snail organism, the functional metal specificity of HpCdMT and HpCuMT was contributed by metal-specific transcription programming and cell-specific expression. Sequence elucidation and phylogenetic analysis of MT isoforms from a number of snail species revealed that they possess an unspecific and two metal-specific MT isoforms, whose metal specificity was achieved exclusively by evolutionary modulation of non-cysteine amino acid positions. The Roman snail HpCdMT and HpCuMT isoforms can thus be regarded as prototypes of isoform families that evolved genuine metal-specificity within pulmonate molluscs. Diversification into these isoforms may have been initiated by gene duplication, followed by speciation and selection towards opposite needs for protecting copper-dominated metabolic pathways from nonessential cadmium. The mechanisms enabling these proteins to be metal-specific could also be relevant for other metalloproteins.
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影响因子：
2.1
作者：
Egli, Dieter;Domenach, Jordi;Atrian, Silvia
通讯作者：
Atrian, Silvia
DOI：
10.1111/j.1432-1033.1993.tb18193.x
发表时间：
1993-09-15
期刊：
EUROPEAN JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
DALLINGER, R;BERGER, B;KAGI, JHR
通讯作者：
KAGI, JHR
影响因子：
4.3
作者：
DALLINGER, R;BERGER, B;BAUERHILTY, A
通讯作者：
BAUERHILTY, A
影响因子：
3.4
作者：
Bofill, Roger;Capdevila, Merce;Atrian, Silvia
通讯作者：
Atrian, Silvia
影响因子：
7.4
作者：
BONGERS, J;WALTON, CD;BELL, JU
通讯作者：
BELL, JU