Metal ion interactions with polyalanine peptides
Metal ion interactions with polyalanine peptides
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DOI：
10.1021/jp049708g
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发表时间：
2004-05-13
影响因子：
3.3
通讯作者：
O'Hair, RAJ
中科院分区：
文献类型：
--
作者：
Kohtani, M;Jarrold, MF;O'Hair, RAJ
电喷雾质谱法和离子迁移率测量已用于执行金属离子和聚丙氨酸肽之间的复杂形成的系统研究。已知单价金属离子（Li+, Na+, K+， Cs+和Rb+）与聚丙氨酸肽形成配合物。在未溶剂化的配合物中，聚丙氨酸肽采用螺旋构象，通过金属离子在c端的配位而稳定。在聚丙氨酸肽和碱土金属（Mg2+, Ca2+， Sr2+和Ba2+）之间也观察到络合物，尽管它们的丰度远远低于与单价离子。未溶剂化的Ala(n) +M2+配合物的离子迁移率测量结果与x-螺旋构象一致，但由于与阳离子的配位更强，在c端出现了大量的螺旋破坏。试图观察与三价金属离子（In3+， Sc3+和Y3+）的络合物形成没有成功。
Electrospray mass spectrometry and ion mobility measurements have been used to perform a systematic study of complex formation between metal ions and polyalanine peptides. Monovalent metal ions (Li+, Na+, K+, Cs+, and Rb+) are known to form complexes with polyalanine peptides. In the unsolvated complex, the polyalanine peptide adopts a helical conformation that is stabilized by coordination of the metal ion to the C-terminus. Complexes are also observed between polyalanine peptides and the dications of alkali earth metals (Mg2+, Ca2+, Sr2+, and Ba2+), though they are substantially less abundant than with the monovalent ions. Ion mobility measurements for the unsolvated Ala(n) +M2+ complexes are consistent with an (x-helical conformation, but with a substantial disruption of the helix at the C-terminus due to much stronger coordination to the dication. Attempts to observe complex formation with trivalent metal ions (In3+, Sc3+, and Y3+) were not successful.