scholarly journals Thermodynamic and Structural Characterization of the Copper(II) Complexes of Peptides Containing Both Histidyl and Aspartyl Residues

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
Csilla Kállay ◽  
Zoltán Nagy ◽  
Katalin Várnagy ◽  
Gerasimos Malandrinos ◽  
Nick Hadjiliadis ◽  
...  
Keyword(s):  
Metal Binding ◽  
Significant Contribution ◽  
Binding Mode ◽  
Side Chain ◽  
Spectroscopic Techniques ◽  
Metal Binding Site ◽  
Carboxylate Groups ◽  
Protected Peptides

Terminally protected pentapeptides with 2 histidines (Ac-HHVGD-NH2and Ac-HVGDH-NH2) and the terminally free peptides containing both internal aspartyl and C-terminal histidyl residues (FDAH and VIDAH) have been synthesized, and copper(II) complexes studied by potentiometric, UV-Vis, CD, and EPR spectroscopic techniques in solution. Both thermodynamic and spectroscopic data reveal that side chain donor atoms of aspartyl and histidyl residues have a significant contribution to the metal binding affinity of peptide molecules. In the case of terminally protected peptides, the role of the imidazole-N donor functions is reflected in the enhanced stability of the 3N and 4N coordinated copper(II) complexes. The amino andβ-carboxylate groups of FDAH and VIDAH create a very effective metal binding site with the (NH2,N−,β-COO−) and (NH2,N−,N−,β-COO−) coordination modes including the N-termini, while the histidine sites are available for the formation of the (Nim,N−,N−) binding mode resulting in the preference of dinuclear complex formation.

scholarly journals Characterization of the dynamics and the conformational entropy in the binding between TAZ1 and CTAD-HIF-1α

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ida Nyqvist ◽  
Jakob Dogan
Keyword(s):  
Entropy Change ◽  
Side Chain ◽  
Transactivation Domain ◽  
Creb Binding Protein ◽  
Conformational Entropy ◽  
Internal Motions ◽  
Relaxation Measurements ◽  
Nanosecond Dynamics

Abstract The interaction between the C-terminal transactivation domain of HIF-1α (CTAD-HIF-1α) and the transcriptional adapter zinc binding 1 (TAZ1) domain of CREB binding protein participate in the initiation of gene transcription during hypoxia. Unbound CTAD-HIF-1α is disordered but undergoes a disorder-to-order transition upon binding to TAZ1. We have here performed NMR side chain and backbone relaxation studies on TAZ1 and side chain relaxation measurements on CTAD-HIF-1α in order to investigate the role of picosecond to nanosecond dynamics. We find that the internal motions are significantly affected upon binding, both on the side chain and the backbone level. The dynamic response corresponds to a conformational entropy change that contributes substantially to the binding thermodynamics for both binding partners. Furthermore, the conformational entropy change for the well-folded TAZ1 varies upon binding to different IDP targets. We further identify a cluster consisting of side chains in bound TAZ1 and CTAD-HIF-1α that experience extensive dynamics and are part of the binding region that involves the N-terminal end of the LPQL motif in CTAD-HIF-1α; a feature that might have an important role in the termination of the hypoxic response.

Characterization of Ligands of a High-Affinity Metal-Binding Site in the Latent Chloroplast F1-ATPase by EPR Spectroscopy of Bound VO2+

Biochemistry ◽  
1994 ◽  
Vol 33 (16) ◽  
pp. 4910-4917 ◽  
Author(s):  
Andrew L. P. Houseman ◽  
Lola Morgan ◽  
Russell LoBrutto ◽  
Wayne D. Frasch
Keyword(s):  
Binding Site ◽  
Epr Spectroscopy ◽  
Metal Binding ◽  
Metal Binding Site ◽  
F1 Atpase ◽  
High Affinity

scholarly journals Role of the htrA Gene in Klebsiella pneumoniae Virulence

2002 ◽  
Vol 70 (9) ◽  
pp. 4772-4776 ◽  
Author(s):  
Guadalupe Cortés ◽  
Beatriz de Astorza ◽  
Vicente J. Benedí ◽  
Sebastián Albertí
Keyword(s):  
Klebsiella Pneumoniae ◽  
Parent Strain ◽  
Structural Features ◽  
Side Chain ◽  
Mice Model ◽  
Complement Component C3 ◽  
Human Sera ◽  
And Oxidative Stress

ABSTRACT We recently described the use of mini-Tn5 to generate complement-sensitive mutants derived from a complement-resistant Klebsiella pneumoniae clinical isolate deficient in the lipopolysaccharide O side chain. One mutant with a reduced capacity to survive in nonimmune human sera carried the transposon inserted in the htrA gene. We cloned and sequenced the gene and predicted from the deduced amino acid sequence that the putative HtrA homolog contains structural features similar to those of previously described HtrA proteins. To investigate the biological functions and the role of the htrA gene in the virulence of K. pneumoniae, we constructed an isogenic mutant by insertion-duplication mutagenesis. Characterization of the mutant showed that it had greater sensitivity to temperature (50°C) and oxidative stress (H2O2) than the parent strain. Furthermore, the htrA mutant produced less capsule, bound more molecules of complement component C3, and was more sensitive to complement and whole-blood killing than was the parent strain. Finally, disruption of the htrA gene in a virulent K. pneumoniae strain caused a reduction of its virulence in a mice model. Our results indicate that the htrA gene plays an important role in the virulence of K. pneumoniae.

scholarly journals The role of copper(ii) in the aggregation of human amylin

Metallomics ◽  
2014 ◽  
Vol 6 (10) ◽  
pp. 1841-1852 ◽  
Author(s):  
Alessandro Sinopoli ◽  
Antonio Magrì ◽  
Danilo Milardi ◽  
Matteo Pappalardo ◽  
Pietro Pucci ◽  
...  
Keyword(s):  
Binding Site ◽  
Metal Binding ◽  
Model Peptide ◽  
Metal Binding Site ◽  
Human Amylin

Copper(ii) coordination to human amylin has an influence on the aggregation and cytotoxic features of the polypeptide. Comparative investigations, carried out on a model peptide encompassing the 17–29 aminoacid region of amylin containing the putative metal binding site, support the non-fibrillar nature of the copper(ii) complexes.

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