scholarly journals A non-canonical metal center drives activity of the Sediminispirochaeta smaragdinae metallo-β- lactamase SPS-1

2018 ◽  
Author(s):  
Zishuo Cheng ◽  
Jamie VanPelt ◽  
Alexander Bergstrom ◽  
Christopher Bethel ◽  
Andrew Katko ◽  
...  
Keyword(s):  
Binding Site ◽  
Active Site ◽  
Metal Binding ◽  
Metal Ion ◽  
Kinetic Studies ◽  
Binding Pocket ◽  
Spectroscopic Studies ◽  
Metal Center ◽  
Spin Coupling ◽  
Metal Binding Site

ABSTRACTIn an effort to evaluate whether a recently reported putative metallo-β-lactamase (MβL) contains a novel MβL active site, SPS-1 from Sediminispirochaeta smaragdinae was over-expressed, purified, and characterized using spectroscopic and crystallographic studies. Metal analyses demonstrate that recombinant SPS-1 binds nearly 2 equivalents of Zn (II), and steady-state kinetic studies show that the enzyme hydrolyzes carbapenems and certain cephalosporins but not β-lactam substrates with bulky substituents in the 6-7 position. Spectroscopic studies on Co (II)-substituted SPS-1 suggest a novel metal center in SPS-1, with reduced spin coupling between the metal ions and a novel Zn1 metal binding site. This site was confirmed with a crystal structure of the enzyme. The structure shows a Zn2 site that is similar that that in NDM-1 and other subclass B1 MβLs; however, the Zn1 metal ion is coordinated by 2 histidine residues and a water molecule, which is held in position by a hydrogen bond network. The Zn1 metal is displaced nearly 1 Å from the position reported in other MβLs. The structure also shows extended helices above the active site, which create a binding pocket that precludes the binding of substrates with large, bulky substituents in the 6/7 position of β-lactam antibiotics. This study reveals a novel metal binding site in MβLs, and suggests that the targeting of metal binding sites in MβLs with inhibitors is now more challenging with the identification of this new MβL.

Efficient localization of a native metal ion within a protein by Cu2+-based EPR distance measurements

2019 ◽  
Vol 21 (20) ◽  
pp. 10238-10243 ◽  
Author(s):  
Austin Gamble Jarvi ◽  
Timothy F. Cunningham ◽  
Sunil Saxena
Keyword(s):  
Binding Site ◽  
Long Range ◽  
Metal Binding ◽  
Metal Ion ◽  
Native Metal ◽  
Distance Measurements ◽  
Metal Binding Site ◽  
Paramagnetic Metal

A native paramagnetic metal binding site in a protein is located with less than 2 Å resolution by a combination of double histidine (dHis) based Cu2+ labeling and long range distance measurements by EPR.

scholarly journals Detailed Insight into the Interaction of Bicyclic Somatostatin Analogue with Cu(II) Ions

2020 ◽  
Vol 21 (22) ◽  
pp. 8794
Author(s):  
Aleksandra Marciniak ◽  
Weronika Witak ◽  
Giuseppina Sabatino ◽  
Anna Maria Papini ◽  
Justyna Brasuń
Keyword(s):  
Binding Site ◽  
Disulfide Bond ◽  
Metal Binding ◽  
Metal Ion ◽  
Magnetic Circular Dichroism ◽  
Intramolecular Interaction ◽  
Peptide Receptor Radionuclide Therapy ◽  
Somatostatin Analogue ◽  
Receptor Binding Site ◽  
Metal Binding Site

Somatostatin analogues are useful pharmaceuticals in peptide receptor radionuclide therapy. In previous studies, we analyzed a new bicyclic somatostatin analogue (BCS) in connection with Cu(II) ions. Two characteristic sites were present in the peptide chain: the receptor- and the metal-binding site. We have already shown that this ligand can form very stable imidazole complexes with the metal ion. In this work, our aim was to characterize the intramolecular interaction that occurs in the peptide molecule. Therefore, we analyzed the coordination abilities of two cyclic ligands, i.e., P1 only with the metal binding site and P2 with both sites, but without the disulfide bond. Furthermore, we used magnetic circular dichroism (MCD) spectroscopy to better understand the coordination process. We applied this method to analyze spectra of P1, P2, and BCS, which we have described previously. Additionally, we analyzed the MCD spectra of P3 ligand, which has only the receptor binding site in its structure. We have unequivocally shown that the presence of the Phe-Trp-Lys-Thr motif and the disulfide bond significantly increases the metal binding efficiency.

scholarly journals Hybrid QM/MM Simulations Confirm Zn(II) Coordination Sphere That Includes Four Cysteines from the P2 × 4R Head Domain

2021 ◽  
Vol 22 (14) ◽  
pp. 7288
Author(s):  
Francisco Andrés Peralta ◽  
J. Pablo Huidobro-Toro ◽  
Raúl Mera-Adasme
Keyword(s):  
Binding Site ◽  
Coordination Sphere ◽  
Metal Binding ◽  
Metal Ion ◽  
Dynamic Simulations ◽  
Metal Binding Site ◽  
Head Domain ◽  
Water Ligands ◽  
Role Of Zn

To ascertain the role of Zn(II) as an allosteric modulator on P2X4R, QM/MM molecular dynamic simulations were performed on the WT and two P2X4R mutants suggested by previous electrophysiological data to affect Zn(II) binding. The Gibbs free energy for the reduction of the putative P2X4R Zn(II) binding site by glutathione was estimated at −22 kcal/mol. Simulations of the WT P2X4R head domain revealed a flexible coordination sphere dominated by an octahedral geometry encompassing C126, N127, C132, C149, C159 and a water molecule. The C132A mutation disrupted the metal binding site, leading to a coordination sphere with a majority of water ligands, and a displacement of the metal ion towards the solvent. The C132A/C159A mutant exhibited a tendency towards WT-like stability by incorporating the R148 backbone to the coordination sphere. Thus, the computational findings agree with previous experimental data showing Zn(II) modulation for the WT and C132A/C159A variants, but not for the C132A mutant. The results provide molecular insights into the nature of the Zn(II) modulation in P2X4R, and the effect of the C132A and C132A/C159A mutations, accounting for an elusive modulation mechanism possibly occurring in other extracellular or membrane protein.

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