Ligand Binding and Protein Dynamics in Cupredoxins

Ehrenstein, D.; Filiaci, M.; Scharf, Birgit E.; Engelhard, Martin; Steinbach, Peter; Nienhaus, G. Ulrich

doi:10.1021/bi00038a010

Cited by 15 publications

(11 citation statements)

References 49 publications

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“…Do both types have similar energy landscapes? Studies of the binding of NO to azurin and another "blue copper" protein, halocyanin, indeed show distributed kinetics and prove that these proteins also have statistical substates [42,43].…”

Section: The Energy Landscape In Different Proteinsmentioning

confidence: 99%

Energy landscape and fluctuations in proteins

Frauenfelder

McMahon

2000

Ann. Phys.

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Complex systems such as biomolecules or glasses do not exist in a unique structure, but can assume a very large number of somewhat different conformations. The organization of the conformations can be described in the energy (or conformation) landscape, where individual valleys are called conformational substates. Proteins are systems where the energy landscape has been studied in some detail. Their landscape is organized in a hierarchy that contains three types of substates, taxonomic, statistical, and few-level. Conformational substates are found in a wide variety of proteins. Some of their characteristics are described and the open experimental and theoretical problems are listed.

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Section: The Energy Landscape In Different Proteinsmentioning

confidence: 99%

Energy landscape and fluctuations in proteins

Frauenfelder

McMahon

2000

Ann. Phys.

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“…It has been reported that type 1 blue copper (T1Cu) proteins and multicopper oxidases (MCOs) can react with NO, with concomitant production of a reversible diamagnetic charge-transfer complex. 21 - 24 However, complete complex formation was only observed at very low temperatures (77 K). 23 At room temperature, only very low extent (∼10 %) of complex formation was observed, even in the presence of saturating concentrations of NO.…”

Section: Introductionmentioning

confidence: 99%

Reversible S-nitrosylation in an engineered azurin

et al. 2016

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S-nitrosothiols are known as reagents for NO storage and transportation, and as regulators in many physiological processes. While the S-nitrosylation catalyzed by heme proteins is well known, no direct evidence of S-nitrosylation in copper proteins has been reported. Here we report reversible insertion of NO into a copper-thiolate bond in an engineered copper center in Pseudomonas aeruginosa azurin by rational design of the primary coordination sphere and tuning its reduction potential via deleting a hydrogen bond in the secondary coordination sphere. The results not only provide the first direct evidence of S-nitrosylation of Cu(II)-bound cysteine within metalloproteins, but also shed light on the reaction mechanism and structural features responsible for stabilizing the elusive Cu(I)-S(Cys)NO species. The fast, efficient, and reversible S-nitrosylation reaction is used to demonstrate its ability to prevent NO inhibition of cytochrome bo3 oxidase activity by competing for NO binding with the native enzyme under physiologically relevant conditions.

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“…Many other heme proteins, for instance, cytochrome oxidase (Alben et al, 1981), cytochrome P450 (Tsubaki et al, 1986;Porter and Coon, 1991), horseradish peroxidase (Doster et al, 1987;Uno et al, 1987), and hemoglobin (Potter et al, 1990), all exhibit multiple CO stretch bands in the CO-ligated form and thus possess A substates. Taxonomic substates are also observed in other classes of protein, for example, retinal proteins and blue copper proteins (Nar et al, 1991;Ehrenstein et al, 1995). Theoretical ideas suggest that these substates are a general property of proteins (Honeycutt and Thirumalai, 1990).…”

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confidence: 97%

Ligand binding to heme proteins. VI. Interconversion of taxonomic substates in carbonmonoxymyoglobin

Johnson

Lamb

Frauenfelder

et al. 1996

Biophysical Journal

132

174

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The kinetic properties of the three taxonomic A substates of sperm whale carbonmonoxy myoglobin in 75% glycerol/buffer are studied by flash photolysis with monitoring in the infrared stretch bands of bound CO at nu(A0) approximately 1967 cm-1, nu(A1) approximately 1947 cm-1, and nu(A3) approximately 1929 cm-1 between 60 and 300 K. Below 160 K the photodissociated CO rebinds from the heme pocket, no interconversion among the A substates is observed, and rebinding in each A substate is nonexponential in time and described by a different temperature-independent distribution of enthalpy barriers with a different preexponential. Measurements in the electronic bands, e.g., the Soret, contain contributions of all three A substates and can, therefore, be only approximately modeled with a single enthalpy distribution and a single preexponential. The bond formation step at the heme is fastest for the A0 substate, intermediate for the A1 substate, and slowest for A3. Rebinding between 200 and 300 K displays several processes, including geminate rebinding, rebinding after ligand escape to the solvent, and interconversion among the A substates. Different kinetics are measured in each of the A bands for times shorter than the characteristic time of fluctuations among the A substates. At longer times, fluctuational averaging yields the same kinetics in all three A substates. The interconversion rates between A1 and A3 are determined from the time when the scaled kinetic traces of the two substates merge. Fluctuations between A1 and A3 are much faster than those between A0 and either A1 or A3, so A1 and A3 appear as one kinetic species in the exchange with A0. The maximum-entropy method is used to extract the distribution of rate coefficients for the interconversion process A0 <--> A1 + A3 from the flash photolysis data. The temperature dependencies of the A substate interconversion processes are fitted with a non-Arrhenius expression similar to that used to describe relaxation processes in glasses. At 300 K the interconversion time for A0 <--> A1 + A3 is 10 microseconds, and extrapolation yields approximately 1 ns for A1 <--> A3. The pronounced kinetic differences imply different structural rearrangements. Crystallographic data support this conclusion: They show that formation of the A0 substate involves a major change of the protein structure; the distal histidine rotates about the C(alpha)-C(beta) bond, and its imidazole sidechain swings out of the heme pocket into the solvent, whereas it remains in the heme pocket in the A1 <--> A3 interconversion. The fast A1 <--> A3 exchange is inconsistent with structural models that involve differences in the protonation between A1 and A3.

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Ligand Binding and Protein Dynamics in Cupredoxins

Cited by 15 publications

References 49 publications

Energy landscape and fluctuations in proteins

Energy landscape and fluctuations in proteins

Reversible S-nitrosylation in an engineered azurin

Ligand binding to heme proteins. VI. Interconversion of taxonomic substates in carbonmonoxymyoglobin

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