Copper(II) interaction with peptide fragments of histidine-proline-rich glycoprotein: Speciation, stability and binding details

详细信息	查看全文 | 推荐本文 |

• 作者：Diego La Mendola^a ; ^{dlamendo@unict.it} ; Antonio Magrì ; ^a ; Anna Maria Santoro^a ; Vincenzo G. Nicoletti^b ; Enrico Rizzarelli^a ; ^b ; ^{erizzarelli@unict.it}
• 关键词：Copper ; Peptide ; Angiogenesis ; HPRG ; Zinc ; Protein
• 刊名：Journal of Inorganic Biochemistry
• 出版年：2012
• 期刊代码：53_01620134
• 类别：ch
• 出版时间：June, 2012
• 卷：111
• 期：Complete
• 页码：59-69
• 文件大小：960 K

摘要

GHHPH is the peptide repeat present in histidine-proline rich glycoprotein (HPRG), a plasma glycoprotein involved in angiogenesis process. The copper(II) ions interaction with mono (Ac-GHHPHG-NH₂) and its bis-repeat (Ac-GHHPHGHHPHG-NH₂) was investigated by means of potentiometric and spectroscopic techniques. To single out the copper(II) coordination environments of different species formed with Ac-GHHPHG-NH₂, three single point mutated peptides were also synthesized and their ability to coordinate Cu²⁺ investigated. Ac-GHHPHG-NH₂ binds Cu²⁺ by the imidazole side chain and the amide nitrogen deprotonation that takes place towards the N-terminus. The bis-repeat is able to bind Cu²⁺ more efficiently than Ac-GHHPHG-NH₂. This difference is not only due to the number of His residues in the sequence but also to the different binding sites. In fact, the comparison of the potentiometric and spectroscopic data of the copper(II) complexes with a bis-repeatPeg construct Ac-(GHHPHG)-Peg-(GHHPHG)-NH₂ and those of the metal complexes with Ac-HGHH-NH₂, indicates that the central HGHH amino acid sequence is the main copper(II) binding site.