Pedersen S A, Kristiansen E, Andersen R A, Zachariassen K E
Department of Biology, Realfagsbygget, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.
Comp Biochem Physiol C Toxicol Pharmacol. 2007 Apr;145(3):457-63. doi: 10.1016/j.cbpc.2007.02.003. Epub 2007 Feb 9.
The effect of cadmium (Cd) exposure on Cd-binding ligands was investigated for the first time in a beetle (Coleoptera), using the mealworm Tenebrio molitor (L) as a model species. Exposure to Cd resulted in an approximate doubling of the Cd-binding capacity of the protein extracts from whole animals. Analysis showed that the increase was mainly explained by the induction of a Cd-binding protein of 7134.5 Da, with non-metallothionein characteristics. Amino acid analysis and de novo sequencing revealed that the protein has an unusually high content of the acidic amino acids aspartic and glutamic acid that may explain how this protein can bind Cd even without cysteine residues. Similarities in the amino acid composition suggest it to belong to a group of little studied proteins often referred to as "Cd-binding proteins without high cysteine content". This is the first report on isolation and peptide sequence determination of such a protein from a coleopteran.
首次以黄粉虫（Tenebrio molitor (L)）为模式物种，在一种甲虫（鞘翅目）中研究了镉（Cd）暴露对镉结合配体的影响。镉暴露导致全动物蛋白质提取物的镉结合能力增加了约一倍。分析表明，这种增加主要是由一种具有非金属硫蛋白特征、分子量为7134.5 Da的镉结合蛋白的诱导所致。氨基酸分析和从头测序显示，该蛋白的酸性氨基酸天冬氨酸和谷氨酸含量异常高，这可能解释了即使没有半胱氨酸残基该蛋白也能结合镉的原因。氨基酸组成的相似性表明它属于一组研究较少的蛋白，常被称为“低半胱氨酸含量的镉结合蛋白”。这是关于从鞘翅目昆虫中分离出此类蛋白并确定其肽序列的首次报道。
