scholarly journals Interference of pH buffer with Pb2+-peripheral domain interactions: obstacle or opportunity?

Metallomics ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 164-172 ◽  
Author(s):  
Sachin Katti ◽  
Tatyana I. Igumenova
Keyword(s):  
Metal Ion ◽  
Membrane Association ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
C2 Domains ◽  
Domain Interactions ◽  
Synaptotagmin 1 ◽  
Ph Buffer ◽  
Peripheral Domain

Pb2+-Chelating pH buffer Bis–Tris enables identification of factors that determine the cooperative metal-ion binding response and membrane association of the Synaptotagmin 1 C2 domains.

scholarly journals Interference of pH buffer with Pb2+-peripheral domain interactions: obstacle or opportunity?

2020 ◽  
Author(s):  
Sachin Katti ◽  
Tatyana I. Igumenova
Keyword(s):  
Binding Sites ◽  
Metal Ion ◽  
Functional Characterization ◽  
Valuable Insight ◽  
Cellular Environment ◽  
Domain Interactions ◽  
Ph Buffer ◽  
Insight Into ◽  
Peripheral Domain

ABSTRACTPb2+ is a xenobiotic metal ion that competes for Ca2+-binding sites in proteins. Using the peripheral Ca2+-sensing domains of Syt1, we show that the chelating pH buffer Bis-Tris enables identification and functional characterization of high-affinity Pb2+ sites that are likely to be targeted by bioavailable Pb2+.Significance to MetallomicsSyt1, a key regulator of Ca2+-evoked neurotransmitter release, is a putative molecular target of Pb2+. We demonstrate that the use of a chelating pH buffer Bis-Tris enables identification of Ca2+-binding sites that would be most susceptible to Pb2+ attack in the cellular environment. In addition, experiments conducted in Bis-Tris revealed the differences between the membrane-binding responses of two Ca2+-sensing domains of Syt1, C2A and C2B. This work advances the understanding of how Pb2+ interacts with multipartite Ca2+-binding sites, and illustrates that conducting the experiments under both chelating and non-chelating conditions could provide valuable insight into the mechanism of metallosensory proteins.

Photophysical Characterisation, Metal Ion Binding and Enantiomeric Recognition of Chiral Ligands Containing Phenazine Fluorophore

2004 ◽  
Vol 69 (4) ◽  
pp. 885-896 ◽  
Author(s):  
Luisa Stella Dolci ◽  
Péter Huszthy ◽  
Erika Samu ◽  
Marco Montalti ◽  
Luca Prodi ◽  
...  
Keyword(s):  
Metal Ion ◽  
Photophysical Properties ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Ammonium Ions ◽  
Enantiomerically Pure ◽  
Binding Process ◽  
High Affinity ◽  
Enantiomeric Recognition ◽  
Chiral Species

Enantiomerically pure dimethyl- and diisobutyl-substituted phenazino-18-crown-6 ligands bind metal and ammonium ions and also primary aralkylammonium perchlorates in acetonitrile with high affinity, causing pronounced changes in their luminescence properties. In addition, they show enantioselectivity towards chiral primary aralkylammonium perchlorates. The possibility to monitor the binding process by photoluminescence spectroscopy can gain ground for the design of very efficient enantioselective chemosensors for chiral species. The observed changes in the photophysical properties are also an important tool for understanding the interactions present in the adduct.

scholarly journals Snapshots of a Non-Canonical RdRP in Action

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1260
Author(s):  
Diego S. Ferrero ◽  
Michela Falqui ◽  
Nuria Verdaguer
Keyword(s):  
Metal Ion ◽  
Rna Viruses ◽  
Ion Binding ◽  
Genome Replication ◽  
Metal Ion Binding ◽  
Insect Virus ◽  
X Ray ◽  
Template Strand ◽  
Nucleotide Incorporation ◽  
Elongation Process

RNA viruses typically encode their own RNA-dependent RNA polymerase (RdRP) to ensure genome replication and transcription. The closed “right hand” architecture of RdRPs encircles seven conserved structural motifs (A to G) that regulate the polymerization activity. The four palm motifs, arranged in the sequential order A to D, are common to all known template dependent polynucleotide polymerases, with motifs A and C containing the catalytic aspartic acid residues. Exceptions to this design have been reported in members of the Permutotetraviridae and Birnaviridae families of positive single stranded (+ss) and double-stranded (ds) RNA viruses, respectively. In these enzymes, motif C is located upstream of motif A, displaying a permuted C–A–B–D connectivity. Here we study the details of the replication elongation process in the non-canonical RdRP of the Thosea asigna virus (TaV), an insect virus from the Permutatetraviridae family. We report the X-ray structures of three replicative complexes of the TaV polymerase obtained with an RNA template-primer in the absence and in the presence of incoming rNTPs. The structures captured different replication events and allowed to define the critical interactions involved in: (i) the positioning of the acceptor base of the template strand, (ii) the positioning of the 3’-OH group of the primer nucleotide during RNA replication and (iii) the recognition and positioning of the incoming nucleotide. Structural comparisons unveiled a closure of the active site on the RNA template-primer binding, before rNTP entry. This conformational rearrangement that also includes the repositioning of the motif A aspartate for the catalytic reaction to take place is maintained on rNTP and metal ion binding and after nucleotide incorporation, before translocation.

The influence of metal-ion binding on the structure and surface composition of Sonic Hedgehog: a combined classical and hybrid QM/MM MD study

2016 ◽  
Vol 18 (32) ◽  
pp. 22254-22265 ◽  
Author(s):  
Manuel Hitzenberger ◽  
Thomas S. Hofer
Keyword(s):  
Metal Ions ◽  
Sonic Hedgehog ◽  
Binding Sites ◽  
Metal Ion ◽  
Surface Composition ◽  
Quantum Mechanical ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Structural Impact

The interaction of metal ions with Shh binding-sites and their structural impact are assessed via classical and quantum mechanical simulations.

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