The glmS catalytic riboswitch is part of the 5'-untranslated region of mRNAs encoding glucosamine-6-phosphate (GlcN6P) synthetase (glmS) in numerous gram-positive bacteria. Binding of the cofactor GlcN6P induces site-specific self-cleavage of the RNA. However, the detailed reaction mechanism as well as the protonation state of the glmS reactive form still remains elusive. To probe the dominant ...

the formation constants of the species formed in the systems h+ + mo(vi) + histidine and h+ +histidine have been determined at different aqueous solutions of methanol (0 - 45 % v/v) at 25 °c andconstant ionic strength (0.1 mol dm-3 sodium perchlorate), using a combination of spectrophotometricand potentiometric techniques. the composition of the complex species was determined by thecontinuous v...

Li7La3Zr 2O12 (LLZO) garnet ceramics are promising electrolytes for all-solid-state lithium-metal batteries with high energy density. However, these prone to Li+/H+ exchange, that is, protonation, resulting in degradation of their Li-ion conductivity. Here, we identify how common processing steps, such as surface cleaning alcohol or acetone, trigger LLZO partial protonation. We deconvolute the ...

Cyproheptadine is one of the compounds exhibiting the highest activity at 5-HT2B receptors. In a previous work we analysed the relevance of the amino group in diphenylmethylenepiperidines (DPMP), which are open cyproheptadine analogues. Only compounds containing N-H or N-methyl motifs, showed significant 5-HT2B activity. Surprisingly, the corresponding quaternary ammonium salt demonstrated a to...

The parent allenediazonium monocation H2C[double bond]C[double bond]CH(N2+) and ten of its substituted derivatives XYC[double bond]C[double bond]C(Z)N2+ (with F, CF3, Me, OMe, and Me2N as substituents) were studied by DFT at the B3LYP/6-31++G** level. Except for the Me2N-substituted derivative that forms a monocation-N2 complex, structurally intact allenediazonium ions were obtained as minima i...

We have studied the apo (Fe(3+) free) form of periplasmic ferric binding protein (FbpA) under different conditions and we have monitored the changes in the binding and release dynamics of H2PO4(-) that acts as a synergistic anion in the presence of Fe(3+). Our simulations predict a dissociation constant in agreement with the experimentally measured value under the same ionic pH conditions. We a...

The protonation site of para-dimethylaminobenzoic acid (p-DMABA) was investigated using atmospheric pressure ionization methods (ESI and APCI) coupled with collision-induced dissociation (CID), nuclear magnetic resonance (NMR), and computational chemistry. Theoretical calculations and NMR experiments indicate that the dimethyl amino group is the preferred site of protonation both in the gas pha...

Theory and experiment indicate that the protonation of reduced NiFe dithiolates proceeds via a previously undetected isomer with enhanced basicity. In particular, it is proposed that protonation of (OC)3Fe(pdt)Ni(dppe) (1; pdt(2-) = (-)S(CH2)3S(-); dppe = Ph2P(CH2)2PPh2) occurs at the Fe site of the two-electron mixed-valence Fe(0)Ni(II) species, not the Fe(I)-Ni(I) bond for the homovalence iso...

Density functional calculations indicate that protonation of a μ3-S atom in cubanoid clusters [Fe4S4X4](2-) leads to a large extension of one Fe-S(H) bond such that the SH ligand is doubly-bridging, μ-SH. Triply-bridging SH in these clusters is unstable, relative to μ-SH. The theory for the geometric and electronic structures of the protonated [Fe4S4X4](2-) clusters (X = Cl, SEt, SMe, SPh, OMe,...

Relying upon the basic tenets of scientific modeling, an ansatz for the evaluation of proton affinity of molecules are evolved in terms of a four component model. The components of the model chosen are global descriptors like ionization energies, global softness, electronegativity and electrophilicity index. These akin quantum mechanical descriptors of atoms and molecules are linked with the ch...