Dissection of Binding between a Phosphorylated Tyrosine Hydroxylase Peptide and 14-3-3ζ: A Complex Story Elucidated by NMR

AbstractHuman tyrosine hydroxylase activity is regulated by phosphorylation of its N-terminus and by an interaction with the modulator 14-3-3 proteins. We investigated the binding of singly or doubly phosphorylated and thiophosphorylated peptides, comprising the first 50 amino acids of human tyrosine hydroxylase, isoform 1 (hTH1), that contain the critical interaction domain, to 14-3-3ζ, by 31P NMR. Single phosphorylation at S19 generates a high affinity 14-3-3ζ binding epitope, whereas singly S40-phosphorylated peptide interacts with 14-3-3ζ one order-of-magnitude weaker than the S19-phosphorylated peptide. Analysis of the binding data revealed that the 14-3-3ζ dimer and the S19- and S40-doubly phosphorylated peptide interact in multiple ways, with three major complexes formed: 1), a single peptide bound to a 14-3-3ζ dimer via the S19 phosphate with the S40 phosphate occupying the other binding site; 2), a single peptide bound to a 14-3-3ζ dimer via the S19 phosphorous with the S40 free in solution; or 3), a 14-3-3ζ dimer with two peptides bound via the S19 phosphorous to each binding site. Our system and data provide information as to the possible mechanisms by which 14-3-3 can engage binding partners that possess two phosphorylation sites on flexible tails. Whether these will be realized in any particular interacting pair will naturally depend on the details of each system

The Eighth Central European Conference "Chemistry towards Biology": snapshot

The Eighth Central European Conference "Chemistry towards Biology" was held in Brno, Czech Republic, on 28 August – 1 September 2016The Eighth Central European Conference "Chemistry towards Biology" was held in Brno, Czech Republic, on 28 August-1 September 2016 to bring together experts in biology, chemistry and design of bioactive compounds; promote the exchange of scientific results, methods and ideas; and encourage cooperation between researchers from all over the world. The topics of the conference covered "Chemistry towards Biology", meaning that the event welcomed chemists working on biology-related problems, biologists using chemical methods, and students and other researchers of the respective areas that fall within the common scope of chemistry and biology. The authors of this manuscript are plenary speakers and other participants of the symposium and members of their research teams. The following summary highlights the major points/topics of the meeting

Experimentalni metody NMR spektroskopie biopolymeru

Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Nucleic acid quadruplexes based on 8‑halo-9-deazaxanthines : energetics and noncovalent interactions in quadruplex stems

Structural and energetic features of arti fi cial DNA quadruplexes consisting of base tetrads and their stacks with Na + /K + ion(s) inside the central pore and incorporating halogenated derivatives of xanthine, 8- fl uoro-9-deazaxanthine (FdaX), 8- chloro-9-deazaxanthine (CldaX), 8-bromo-9-deazaxanthine (BrdaX), or 8-iodo-9-deazaxanthine (IdaX), have been investigated by modern state-of-the-art computational tools. The DNA (or RNA) quadruplex models based on 8-halo-9-deazaxanthines are predicted to be more stable relative to those with unmodi fi ed xanthine due to the increased stabilizing contributions coming from all three main types of weak interactions (H-bonding, stacking, and ion coordination). Methods for analyzing the electron density are used to understand the nature of forces determining the stability of the system and to gain a predictive potential. Quadruplex systems incorporating polarizable halogen atoms (chlorine, bromine, or iodine) bene fi t signi fi cantly from the stabilizing stacking between the individual tetrads due to an increased dispersion contribution as compared to xanthine and guanine, natural references used. Ion coordination induces a signi fi cant rearrangement of electron density in the quadruplex stem as visualized by electron deformation density (EDD) and analyzed by ETS-NOCV and Voronoi charges. Na + induces larger electron polarization from the quadruplex toward the ion, whereas K + has a higher propensity to electron sharing (identi fi ed by QTAIM delocalization index). We expect that our results will contribute to the development of novel strategies to further modify and analyze the natural G-quadruplex core

Structure of Bombyx mori chemosensory protein 1 in solution

Chemosensory Proteins (CSPs) represent a family of conserved proteins found in insects that may be involved in chemosensory functions. BmorCSP1 is expressed mainly in antennae and legs of the silkworm moth Bombyx morii and was cloned from antennal cDNA. Here we report the determination of the structure of Bombyx mori CSP1 (BmorCSP1) by NMR. The overall fold of BmorCSP1 is globular and comprises six a-helices. These helices span residues 10-14, 17-27, 35-49, 57-72, 75-85, and 92-100. The internal hydrophobic sides of the helices are formed mostly by leucine and isoleucine residues and, therefore, well suited to constitute a binding site for hydrophobic ligands

Spectral density mapping at multiple magnetic fields suitable for C-13 NMR relaxation studies

Standard spectral density mapping protocols, well suited for the analysis of N-15 relaxation rates, introduce significant systematic errors when applied to C-13 relaxation data, especially if the dynamics is dominated by motions with short correlation times (small molecules, dynamic residues of macromolecules). A possibility to improve the accuracy by employing cross-correlated relaxation rates and on measurements taken at several magnetic fields has been examined. A suite of protocols for analyzing such data has been developed and their performance tested. Applicability of the proposed protocols is documented in two case studies, spectral density mapping of a uniformly labeled RNA hairpin and of a selectively labeled disaccharide exhibiting highly anisotropic tumbling. Combination of auto- and cross-correlated relaxation data acquired at three magnetic fields was applied in the former case in order to separate effects of fast motions and conformational or chemical exchange. An approach using auto-correlated relaxation rates acquired at five magnetic fields, applicable to anisotropically moving molecules, was used in the latter case. The results were compared with a more advanced analysis of data obtained by interpolation of auto-correlated relaxation rates measured at seven magnetic fields, and with the spectral density mapping of cross-correlated relaxation rates. The results showed that sufficiently accurate values of auto- and cross-correlated spectral density functions at zero and C-13 frequencies can be obtained from data acquired at three magnetic fields for uniformly C-13-labeled molecules with a moderate anisotropy of the rotational diffusion tensor. Analysis of auto-correlated relaxation rates at five magnetic fields represents an alternative for molecules undergoing highly anisotropic motions