The<scp>L</scp>-proline residue as a ‘break-point’ in the co-ordination of metal–peptide systems

Bataille, Michel; Formicka-Kozlowska, Grazyna; Kozłowski, Henryk; Pettit, Leslie D.; Steel, Ian

doi:10.1039/c39840000231

Cited by 36 publications

(26 citation statements)

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“…7) suggests that in both monomeric complexes additional amide nitrogen atoms are involved in metal coordination. The same binding pattern was observed for proline containing peptides, in which the Pro residue in the peptide sequence acts as a break-point [63][64][65]. The N tetr donor is weakly basic and thus sensitive to hydrolysis at high pH.…”

Section: Copper(ii) Complexes With the Tetrazole Analogue Of Tetraalasupporting

confidence: 71%

Tetrazole peptides as copper(II) ion chelators

Łodyga-Chruścińska¹

2011

Coordination Chemistry Reviews

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Section: Copper(ii) Complexes With the Tetrazole Analogue Of Tetraalasupporting

confidence: 71%

Tetrazole peptides as copper(II) ion chelators

Łodyga-Chruścińska¹

2011

Coordination Chemistry Reviews

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“…The tertiary histidylprolinamide is, however, a weak donor [16], thus TRH may act as a dipeptide. The molecular binding stoichiometry was determined using "the method of continuous variation", or Job's plot (Fig.…”

Section: The Binding Stoichiometrymentioning

confidence: 99%

Binding of copper(II) to thyrotropin-releasing hormone (TRH) and its analogs

Rong¹,

Becker²,

Lin³

et al. 2005

Inorganica Chimica Acta

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Spectroscopy (UV-Vis, 1 H NMR, ESR) and electrochemistry revealed details of the structure of the Cu(II)-TRH (pyroglutamyl-histidyl-prolyl amide) complex. The 1 H NMR spectrum of TRH has been assigned. NMR spectra of TRH in the presence of Cu(II) showed that Cu(II) initially binds TRH through the imidazole. TRH analogs, pGlu-His-Pro-OH, pGlu-(1-Me)His-Pro-amide, pGlu-His-(3,4-dehydro)Pro-amide, pGlu-His-OH, pGlu-Glu-Pro-amide, and pGlu-Phe-Pro-amide provided comparison data. The stoichiometry of the major Cu(II)-TRH complex at pH 7.45 and greater is 1:1. The conditional formation constant (in pH 9.84 borate with 12.0 mM tartrate) for the formation of the complex is above 10 5 M −1 . The coordination starts from the 1-N of the histidyl imidazole, and then proceeds along the backbone involving the deprotonated pGlu-His amide and the lactam nitrogen of the pGlu residue. The fourth equatorial donor is an oxygen donor from water. Hydroxide begins to replace the water before the pH reaches 11. Minority species with stoichiometry of Cu-(TRH) x (x = 2-4) probably exist at pH lower than 8.0. In non-buffered aqueous solutions, TRH acts as a monodentate ligand and forms a Cu(II)-(TRH) 4 complex through imidazole nitrogens. All the His-containing analogs behave like TRH in terms of the above properties.

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“…Because of the remarkably high proportion of proline residues, a structure that is not characteristic for random coil is proposed for the copper-free form of the avian PrP repeats (31,34). Based on sterical constraints, Pro residues are also known to act as "break-points" in the coordination of donor centers of the peptide chain to metal ions (49). In particular, the presence of Pro at position 4 in the chicken hexapeptide excludes the involvement of a second amide nitrogen in the Cu(II) coordination, as is observed for mammalian mono-octarepeats (11,27,34,35).…”

Section: Cu(ii) Site Geometry In the Chickenmentioning

confidence: 99%

Comparative Analysis of the Human and Chicken Prion Protein Copper Binding Regions at pH 6.5

Redecke

Meyer‐Klaucke

Koker

et al. 2005

Journal of Biological Chemistry

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Recent experimental evidence supports the hypothesis that prion proteins (PrPs) are involved in the Cu(II) metabolism. Moreover, the copper binding region has been implicated in transmissible spongiform encephalopathies, which are caused by the infectious isoform of prion proteins (PrP Sc ). In contrast to mammalian PrP, avian prion proteins have a considerably different Nterminal copper binding region and, most interestingly, are not able to undergo the conversion process into an infectious isoform. Therefore, we applied x-ray absorption spectroscopy to analyze in detail the Cu(II) geometry of selected synthetic human PrP Cu(II) octapeptide complexes in comparison with the corresponding chicken PrP hexapeptide complexes at pH 6.5, which mimics the conditions in the endocytic compartments of neuronal cells. Our results revealed that structure and coordination of the human PrP copper binding sites are highly conserved in the pH 6.5-7.4 range, indicating that the reported pH dependence of copper binding to PrP becomes significant at lower pH values. Furthermore, the different chicken PrP hexarepeat motifs display homologous Cu(II) coordination at sub-stoichiometric copper concentrations. Regarding the fully cationsaturated prion proteins, however, a reduced copper coordination capability is supposed for the chicken prion protein based on the observation that chicken PrP is not able to form an intra-repeat Cu(II) binding site. These results provide new insights into the prion protein structure-function relationship and the conversion process of PrP.

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TheL-proline residue as a ‘break-point’ in the co-ordination of metal–peptide systems

Abstract: The L-proline residue in oligopeptides has been shown to act as a 'break-point' in their co-ordination to copper(ii) ions leading to the formation of large chelate rings with the peptide locked in the (3-conformation.

Cited by 36 publications

References 0 publications

Tetrazole peptides as copper(II) ion chelators

Tetrazole peptides as copper(II) ion chelators

Binding of copper(II) to thyrotropin-releasing hormone (TRH) and its analogs

Comparative Analysis of the Human and Chicken Prion Protein Copper Binding Regions at pH 6.5

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