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Interactions of disulfide-constrained cyclic tetrapeptides with Cu(2+).
MedLine Citation:
PMID:  23340690     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The purpose of this work is to characterize the interactions of two disulfide-constrained cyclic tetrapeptides [c(Ac-Cys-Pro-Phe-Cys-NH(2)), SS1; c(Ac-Cys-Pro-Gly-Cys-NH(2)), SS2] with Cu(2+) ions in order to facilitate the design of cyclic peptides as sensors for metal ions. The Cu(2+)-peptide complex cations at m/z 569.1315 for Cu(2+)-SS1 and m/z 479.0815 for Cu(2+)-SS2 were detected by mass spectrometry. The gas-phase fragmentation of the Cu(2+)-peptide complexes was studied by collision-induced dissociation and suggests the atoms involved in the coordination. Cu(2+) ion binds to a single SS1 or SS2 with K (d(app)) of 0.57 ± 0.02 and 0.55 ± 0.01 μM, respectively. Isothermal titration calorimetry data indicate both enthalpic and entropic contributions for the binding of Cu(2+) ion to SS1 and SS2. The characteristic wavenumber of 947 cm(-1) and the changes at 1,664 and 1,530 cm(-1) in the infrared spectrum suggest that the sulfydryl of cysteine, the carbonyl group, and amide II are involved in the coordination of Cu(2+). The X-ray absorption near-edge structure signal from the Cu(2+)-peptide complex corresponds to the four-coordination structure. The extended X-ray absorption fine structure and electron paramagnetic resonance results demonstrate the Cu(2+) ion is in an S/N/2O coordination environment, and is a distinct type II copper center. Theoretical calculations further demonstrate that Cu(2+) ion binds to SS1 or SS2 in a slightly distorted tetragonal geometry with an S/N/2O environment and the minimum potential energy.
Authors:
Liyun Zhang; Zhaofeng Luo; Lidong Zhang; Liangyuan Jia; Lifang Wu
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-23
Journal Detail:
Title:  Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry     Volume:  -     ISSN:  1432-1327     ISO Abbreviation:  J. Biol. Inorg. Chem.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-23     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9616326     Medline TA:  J Biol Inorg Chem     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, 230031, People's Republic of China, zly0605@ustc.edu.cn.
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