scholarly journals Bivalent-metal binding to CheY protein. Effect on protein conformation

1992 ◽  
Vol 287 (2) ◽  
pp. 521-531 ◽  
Author(s):  
L Kar ◽  
P Matsumura ◽  
M E Johnson
Keyword(s):  
Metal Ions ◽  
Conformational Change ◽  
Metal Binding ◽  
Bound States ◽  
Aromatic Proton ◽  
Double Quantum ◽  
Two Dimensional ◽  
Coherence Transfer ◽  
Bivalent Metal ◽  
Metal Free

CheY is a 14 kDa cytoplasmic protein that is activated by the transfer of a phosphoryl moiety to Asp-57 from phosphoCheA during signal transduction in bacterial chemotaxis. It has been established that metal ions are necessary for the autophosphorylation of CheA, the transfer of phosphate from phosphoCheA to CheY and the autodephosphorylation of phosphoCheY. In this work, paramagnetic relaxation enhancement has been used in conjunction with one- and two-dimensional n.m.r. to study the interaction of CheY with bivalent metal ions. These studies have led to the discovery of two conformations of the protein in water, corresponding to the metal-free and the metal-bound states. Binding of bivalent cations like Mg2+, Ca2+, Sr2+, Zn2+ and Mn2+ results in a conformational change from the metal-free to the metal-bound state. Preliminary assignments of the aromatic proton resonances are reported. Comparison of phase-sensitive double-quantum-filtered COSY, homonuclear Hartmann-Hahn coherence transfer and nuclear Overhauser enhancement spectra from the metal-bound and metal-free protein indicates that Trp-58, Thr-87 and Tyr-106 are particularly affected by the conformational change involved, and that this change is limited to a small number of residues. In addition, homonuclear Hartmann-Hahn coherence transfer experiments with paramagnetic Mn2+ show significant suppression of cross-peaks associated with Trp-58 and several neighbouring residues. Comparison of the distances estimated using n.m.r. with the CheY crystal structure indicates that the n.m.r. results are consistent with bivalent metal binding at the cluster of aspartic acid residues that includes Asp-13 and Asp-57. These studies also demonstrate the utility of paramagnetic metal-induced relaxation in conjunction with two-dimensional n.m.r. measurements for exploring ligand-binding sites.

scholarly journals Conformation and dynamics of the deoxyribose rings of a (nogalamycin)2–d (5′-GCATGC)2 complex studied in solution by 1H-n.m.r. spectroscopy

1990 ◽  
Vol 269 (2) ◽  
pp. 341-346 ◽  
Author(s):  
M S Searle ◽  
L P Wakelin
Keyword(s):  
Base Pair ◽  
Dynamic Equilibrium ◽  
Graphical Analysis ◽  
Correlation Spectroscopy ◽  
Coupling Constants ◽  
Double Quantum ◽  
Two Dimensional ◽  
Coherence Transfer ◽  
Data Set ◽  
Base Pair Stacking

The conformation and dynamics of the deoxyribose rings of a (nogalamycin)2-d(5′-GCATGC)2 complex have been determined from an analysis of 1H-1H vicinal coupling constants and sums of coupling constants (J1′-2′,J1′-2″,epsilon 1′, epsilon 2′ and epsilon 2″) measured from one-dimensional n.m.r. spectra and from H-1′-H-2′ and H-1′-H-2″ cross-peaks in high-resolution phase-sensitive two-dimensional correlation spectroscopy (COSY) and double-quantum-filtered correlation spectroscopy (DQF-COSY) experiments. The value of J3′-4′ has also been estimated from the magnitude of H-3′-H-4′ cross-peaks in DQF-COSY spectra and H-1′-H-4′ coherence transfer cross-peaks in two-dimensional homonuclear Hartman-Hahn spectroscopy (HOHAHA) spectra. The data were analysed, in terms of a dynamic equilibrium between North (C-3′-endo) and South (C-2′-endo) conformers, by using the graphical-analysis methods described by Rinkel & Altona [(1987) J. Biomol. Struct. Dyn. 4,621-649]. The data reveal that the sugars of the 2C-5G and 3A-4T base-pairs, which form the drug-intercalation site, have strikingly different properties. The deoxyribose rings of the 2C-5G base-pair are best described in terms of an equilibrium heavily weighted in favour of the C-2′-endo geometry (greater than 95% ‘S’), with a phase angle, P, lying in the range 170-175 degrees and amplitude of pucker between 35 and 40 degrees, as typically found for B-DNA. For the deoxyribose rings of the 3A-4T base-pair, however, the analysis shows that, for 3A, the C-2′-endo and C3′-endo conformers are equally populated, whereas a more limited data set for the 4T nucleotide restricts the equilibrium to within 65-75% C-2′-endo. The deoxyribose rings of the 1G-6C base-pair have populations of 70-80% C-2′-endo, typical of nucleotides at the ends of a duplex. Although drug-base-pair stacking interactions are an important determinant of the enhanced duplex stability of the complex [Searle, Hall, Denny, & Wakelin (1988) Biochemistry 27, 4340-4349], the current findings make it clear that the same interactions can be associated with considerable variations in the degree of local structural dynamics at the level of the sugar puckers.

scholarly journals Deferoxamine B: A Natural, Excellent and Versatile Metal Chelator

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3255
Author(s):  
Denise Bellotti ◽  
Maurizio Remelli
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Chelation Therapy ◽  
Iron Chelation ◽  
Binding Ability ◽  
Complex Formation Equilibria ◽  
Metal Chelator ◽  
The Past ◽  
Formation Equilibria ◽  
Terminal Amino

Deferoxamine B is an outstanding molecule which has been widely studied in the past decade for its ability to bind iron and many other metal ions. The versatility of this metal chelator makes it suitable for a number of medicinal and analytical applications, from the well-known iron chelation therapy to the most recent use in sensor devices. The three bidentate hydroxamic functional groups of deferoxamine B are the centerpiece of its metal binding ability, which allows the formation of stable complexes with many transition, lanthanoid and actinoid metal ions. In addition to the ferric ion, in fact, more than 20 different metal complexes of deferoxamine b have been characterized in terms of their chemical speciation in solution. In addition, the availability of a terminal amino group, most often not involved in complexation, opens the way to deferoxamine B modification and functionalization. This review aims to collect and summarize the available data concerning the complex-formation equilibria in solutions of deferoxamine B with different metal ions. A general overview of the progress of its applications over the past decade is also discussed, including the treatment of iron overload-associated diseases, its clinical use against cancer and neurodegenerative disorders and its role as a diagnostic tool.

scholarly journals Metal Binding Proteins

Encyclopedia ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 261-292
Author(s):  
Eugene A. Permyakov
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Transition Metal Ions ◽  
Short Review ◽  
Sodium Potassium ◽  
Physical Chemical ◽  
Physiological Properties ◽  
Cell Processes ◽  
Living Organisms ◽  
Potassium Magnesium

Metal ions play several major roles in proteins: structural, regulatory, and enzymatic. The binding of some metal ions increase stability of proteins or protein domains. Some metal ions can regulate various cell processes being first, second, or third messengers. Some metal ions, especially transition metal ions, take part in catalysis in many enzymes. From ten to twelve metals are vitally important for activity of living organisms: sodium, potassium, magnesium, calcium, manganese, iron, cobalt, zinc, nickel, vanadium, molybdenum, and tungsten. This short review is devoted to structural, physical, chemical, and physiological properties of proteins, which specifically bind these metal cations.

Two-dimensional triazine-based porous framework as a novel metal-free bifunctional electrocatalyst for zinc-air batty

2021 ◽  
Vol 591 ◽  
pp. 253-263
Author(s):  
Jiameng Liu ◽  
Changbao Wang ◽  
Yingpan Song ◽  
Shuai Zhang ◽  
Zhihong Zhang ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Bifunctional Electrocatalyst ◽  
Metal Free ◽  
Porous Framework
Sign in / Sign up

Export Citation Format

Share Document