Evidence regarding the hypothesis that the histidine–histidine contact pairs may affect protein stability

Haghani, Karimeh; Khajeh, Khosro; Naderi-Manesh, Hossein; Ranjbar, Bijan

doi:10.1016/j.ijbiomac.2011.12.009

Cited by 9 publications

(6 citation statements)

References 36 publications

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“…Such contacts disappear when the contact partners become charged by protonation, but in a salt-independent manner. Recent studies are in support of this concept and suggest that the imidazole rings of two neutral histidine side chains can form transient hydrogen bonds and also π–π stabilized contact pairs with one ring stacked upon the other. − In addition, the MD simulations indicated significantly increased main chain–side chain interactions in neutral His 6 (Supporting Information Table S1); only the neutral imidazole ring can act as both hydrogen-bond donor and acceptor for the peptide backbone. In summary, the His 6 peptide experiences an apparent compaction upon deprotonation due to increased specific intrachain interactions, which accounts for the fact that the effective end-to-end distance is rather insensitive to the presence of salts, but nevertheless sensitive to pH.…”

Section: Discussionmentioning

confidence: 87%

Coulomb Repulsion in Short Polypeptides

et al. 2014

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Coulomb repulsion between like-charged side chains is presently viewed as a major force that impacts the biological activity of intrinsically disordered polypeptides (IDPs) by determining their spatial dimensions. We investigated short synthetic models of IDPs, purely composed of ionizable amino acid residues and therefore expected to display an extreme structural and dynamic response to pH variation. Two synergistic, custom-made, time-resolved fluorescence methods were applied in tandem to study the structure and dynamics of the acidic and basic hexapeptides Asp6, Glu6, Arg6, Lys6, and His6 between pH 1 and 12. (i) End-to-end distances were obtained from the short-distance Förster resonance energy transfer (sdFRET) from N-terminal 5-fluoro-l-tryptophan (FTrp) to C-terminal Dbo. (ii) End-to-end collision rates were obtained for the same peptides from the collision-induced fluorescence quenching (CIFQ) of Dbo by FTrp. Unexpectedly, the very high increase of charge density at elevated pH had no dynamical or conformational consequence in the anionic chains, neither in the absence nor in the presence of salt, in conflict with the common view and in partial conflict with accompanying molecular dynamics simulations. In contrast, the cationic peptides responded to ionization but with surprising patterns that mirrored the rich individual characteristics of each side chain type. The contrasting results had to be interpreted, by considering salt screening experiments, N-terminal acetylation, and simulations, in terms of an interplay of local dielectric constant and peptide-length dependent side chain charge-charge repulsion, side chain functional group solvation, N-terminal and side chain charge-charge repulsion, and side chain-side chain as well as side chain-backbone interactions. The common picture that emerged is that Coulomb repulsion between water-solvated side chains is efficiently quenched in short peptides as long as side chains are not in direct contact with each other or the main chain.

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Section: Discussionmentioning

confidence: 87%

Coulomb Repulsion in Short Polypeptides

et al. 2014

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“…The superior affinity of CyHis is associated with the unique characteristics of imidazole that can be engaged in a wide range of non-covalent interactions (ionic, H bonds as donor or acceptor, and through its π aromatic cloud) which play crucial structural roles in protein structure, interactions and function. 53–59…”

Section: Resultsmentioning

confidence: 99%

Pseudopeptidic host adaptation in peptide recognition unveiled by ion mobility mass spectrometry

Tapia

Pérez

Solà

et al. 2022

Analyst

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“…The PCR product was cloned into the expression vector pET21a (+). Bacillus amyloliquefaciens was cultured in medium containing (g/l) peptone (5), meat extract (3), agar (15), and MnSO 4 •H 2 O (0.01) at 30 o C. Escherichia coli strains were grown overnight in Luria-Bertani (LB) medium [27] at 37 o C.…”

Section: Methodsmentioning

confidence: 99%

“…The α-amylase gene was amplified from purified total DNA using the polymerase chain reaction (PCR). The PCR product was digested with NdeI and NotI restriction enzymes and ligated into the restriction enzymes-cleaved pET21a (+) with T4 DNA ligase at 37 o C for 12 h [15]. Then the ligation mixture was transformed into E. coli XL1 Blue [6].…”

Section: Cloning Of the Baa Gene In Pet21amentioning

confidence: 99%

Role of the Salt Bridge Between Arg176 and Glu126 in the Thermal Stability of the Bacillus amyloliquefaciens α-Amylase (BAA)

Zonouzi

Khajeh²,

Monajjemi³

et al. 2013

J. Microbiol. Biotechnol.

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In the Bacillus amyloliquefaciens α-amylase (BAA), the loop (residues 176-185; region I) that is the part of the calcium-binding site (CaI, II) has two more amino acid residues than the α-amylase from Bacillus licheniformis (BLA). Arg176 in this region makes an ionic interaction with Glu126 from region II (residues 118-130), but this interaction is lost in BLA owing to substitution of R176Q and E126V. The goal of the present work was to quantitatively estimate the effect of ionic interaction on the overall stability of the enzyme. To clarify the functional and structural significance of the corresponding salt bridge, Glu126 was deleted (ΔE126) and converted to Val (E126V), Asp (E126D), and Lys (E126K) by site-directed mutagenesis. Kinetic constants, thermodynamic parameters, and structural changes were examined for the wild-type and mutated forms using UV-visible, atomic absoption, and fluorescence emission spectroscopies. Wild type exhibited higher k(cat) and K(m) but lower catalytic efficiency than the mutant enzymes. A decreased thermostability and an increased flexibility were also found in all of the mutant enzymes when compared with the wild type. Additionally, the calcium content of the wild type was more than ΔE126. Thus, it may be suggested that ionic interaction could decrease the mobility of the discussed region, prevent the diffusion of cations, and improve the thermostability of the whole enzyme. Based on these observations, the contribution of loop destabilization may be compensated by the formation of a salt bridge that has been used as an evolutionary mechanism or structural adaptation by the mesophilic enzyme.

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Evidence regarding the hypothesis that the histidine–histidine contact pairs may affect protein stability

Cited by 9 publications

References 36 publications

Coulomb Repulsion in Short Polypeptides

Coulomb Repulsion in Short Polypeptides

Pseudopeptidic host adaptation in peptide recognition unveiled by ion mobility mass spectrometry

Role of the Salt Bridge Between Arg176 and Glu126 in the Thermal Stability of the Bacillus amyloliquefaciens α-Amylase (BAA)

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