[Show abstract][Hide abstract] ABSTRACT: The angular dependencies of inelastic intensities of Rayleigh scatteringof Moessbauer radiation were measured for lysozyme and myoglobin (fordifferent degrees of hydration: from h = 0.05 till h = 0.7). The treating ofthe data at h > 0.05 approves the existence of segmental motions(α-helices for myoglobin, α-helices and β-sheets forlysozyme) as well as of individual motions. Further hydration increase themean-square displacements for both types of intraglobular motions for theseproteins, while the motions of the globule as a whole remain nearlythe same as for h = 0.05. Results of the study of the radial distributionfunction deduced by Fourier - transform from the diffuse x-raymeasurements together with RSMR data allow to conclude that the waterduring hydration of proteins competes with the intramolecular hydrogenbonds, loosens the protein and increases the internal dynamics. At the sametime water arranges the ordering of macromolecule from `glassy' state ath ≈ 0.02 to the native state at h = 0.4-0.7. Differentarchitecture of proteins leads to the different structural dynamics as in thecase of lysozyme and myoglobin.
Preview · Article · Jun 2002 · Journal of Biological Physics
[Show abstract][Hide abstract] ABSTRACT: The angular dependencies of inelastic intensities of Rayleigh scattering of Mössbauer radiation were measured for lysozyme and myoglobin (for different degrees of hydration: from h=0.05 till h=0.7). The treating of the data at h>0.05 approves the existence of segmental motions (α-helices for myoglobin, α-helices and -sheets for lysozyme) as well as of individual motions. Further hydration increases the mean-square displacements for both types of intraglobular motions for these proteins, while the motions of the globule as a whole remain nearly the same as for h=0.05. Results of the study of the radial distribution function deduced by Fourier-transform from the diffuse X-ray measurements together with RSMR data allow to conclude that the water during hydration of proteins competes with the intramolecular hydrogen bonds, loosens the protein and increases the internal dynamics. At the same time water arranges the ordering of macromolecule from “glassy” state at h≈0.02 to the native state at h=0.4–0.7. Different architecture of proteins leads to the different structural dynamics as in the case of lysozyme and myoglobin.
No preview · Article · Jan 2002 · Hyperfine Interactions
[Show abstract][Hide abstract] ABSTRACT: Protein specific modes of motions are found in myoglobin crystals above 180 K. In this contribution we show that this type of motions can be analyzed by a Davidson-Cole, a Cole-Cole or a Havriliak-Negami distribution in analogy to dielectric relaxation. However, the temperature dependence of the obtained parameters is quite unusual indicating a broadening of the distributions with temperature instead of motional narrowing. This can be understood from the picture of conformational substates if one assumes that more and more substates become accessible with increasing temperature. The result shows that the analogy between glass forming organic liquids and proteins should not be exaggerated.
No preview · Article · Nov 1996 · Chemical Physics
[Show abstract][Hide abstract] ABSTRACT: Summary The classical model system poly-L-glutamic acid (poly-Glu), was investigated in a disordered coil state (at pH=7.0) and in helix state (at pH=2.0) by the RSMR technique. By considering that the coil state of poly-Glu models unfolded (random coil) state and α-helix
state models the fluctuating secondary structure (during consequent folding of protein), a comparative analysis of the dynamical
properties of poly-Glu in different states with the dynamical properties of different proteins in the native state (α-helical
myoglobin and HSA, partially β-sheet lysozyme) and in intermediate (molten globule) state (α-lactalbumin) was performed. This
comparison brings some unpredicted results: native α-helical proteins behave close to random coil, native partially β-sheet
proteins behave close to fluctuating secondary structure (α-helix) and the dynamic behaviour of molten-globule state (partially
β-sheet α-lactalbumin) is not different from the behaviour of lysozyme and much more rigid than that of native α-helical proteins.
No preview · Article · Feb 1996 · Il Nuovo Cimento D
[Show abstract][Hide abstract] ABSTRACT: The method of differential diathermic calorimetry was used to obtain the curves of release and absorption of heat in water—protein systems. The influences of the rates of cooling and heating and the influence of annealing on the state of a water—lysozyme system at different hydration degrees h = 0.1−0.7 g/g were studied. Experiments have demonstrated that at considerably large rates of cooling there are observed the effects of vitrification of water—protein systems, i.e. the stabilization of a metastable, nonequilibrium structure of system. Decrease of the cooling rate or annealing transforms more of the system into an equilibrium state, increasing the degree of globular crystallinity to more than 70%. Therefore low-temperature experiments with water—protein systems aimed at obtaining functionally important information (i.e. important also at room temperatures) should be performed with slowly cooled or with annealed systems.
No preview · Article · Jun 1993 · Chemical Physics Letters
[Show abstract][Hide abstract] ABSTRACT: In this survey, the scales and correlation times of the motion of iron atoms in the active site of myoglobin and hemoglobin,
in the iron containing core, in iron storage proteins, and model polymer systems, and the average fragmental motion of protein
globules of myoglobin and human serum albumin are considered. Models of intramolecular protein mobility are presented.
No preview · Article · Nov 1991 · Hyperfine Interactions
[Show abstract][Hide abstract] ABSTRACT: A comparative study of a native and molten globule state of α-lactalbumin and polyglutamic acid in helical and coiled states
were performed by RSMR. Molten globule state possesses the same dynamical features registrated by RSMR as the native one.
Large-scale low-frequency motions were registrated in the coiled molecule without any elements of secondary structure.
No preview · Article · Nov 1991 · Hyperfine Interactions
[Show abstract][Hide abstract] ABSTRACT: In the survey, the scales and correlation times of motion on different levels are considered: iron atoms in active centre
of myoglobin and hemoglobin, iron containing core in iron storage proteins and model polymer systems, and the average fragmental
motion of a protein globule of myoglobin and human serum albumin. The models of intramolecular protein mobility have been
No preview · Article · Dec 1990 · Applied Magnetic Resonance
[Show abstract][Hide abstract] ABSTRACT: Recent experimental results on the study of intramolecular mobility of hydrated DNA by RSMR are presented. Hydrated DNA possesses
a well-developed mobility: X
2> reaches 1.2 2 at high hydration degree. RSMR spectra were measured for hydrated DNA within a temperature range of 90 K-300 K. A quasielastic
“wide” component was observed atT>260 K. Three different types of intramolecular mobility were introduced for description of experimental data.
No preview · Article · Jul 1990 · Hyperfine Interactions
[Show abstract][Hide abstract] ABSTRACT: A critical review of recent studies of protein dynamics by the RSMR technique is given. The main approximations in quantitative analyses of RSMR data are discussed and conclusions about dynamical properties of protein and interprotein water, deduced from experiments, are described.
No preview · Article · Jan 1990 · Hyperfine Interactions
[Show abstract][Hide abstract] ABSTRACT: A method of Mössbauer Fourier spectroscopy is developed to determine the correlation function of coordinates of a macromolecular
system. The method does not require the use of an a priori dynamic model. The application of the method to the analysis of
RSMR data for human serum albumin has demonstrated considerable changes in the dynamic behavior of the protein globule when
the temperature is changed from 270 to 310 K. The main conclusions of the present work is the simultaneous observation of
low-frequency (τ≥10−9 sec) and high-frequency (τ≪10−9 sec) large-scaled motions, that is the two-humped distribution of correlation times of protein motions.
Full-text · Article · Nov 1988 · Hyperfine Interactions
[Show abstract][Hide abstract] ABSTRACT: Data on the electronic state of iron in active centres of heme proteins and on the dynamics of these proteins have been obtained by means of Mössbauer spectroscopy and Rayleigh scattering of Mössbauer radiation. The influence of conformational rearrangements of the protein globule on the electronic state of the iron atom is considered. Mean square displacements of the iron atom and average mean square displacements of the myoglobin globule are compared.
No preview · Article · Sep 1988 · Journal of Molecular Catalysis
[Show abstract][Hide abstract] ABSTRACT: A review of recent experimental results on the study of protein dynamics by the Rayleigh scattering of Mössbauer radiation
(RSMR) method is given. Dynamical properties of protein and protein-bound water, deduced from a quantitative analysis of RSMR
data, are described.
No preview · Article · Jan 1988 · Hyperfine Interactions
[Show abstract][Hide abstract] ABSTRACT: The paper examines the conditions (range of degrees of hydration and temperatures) in which the effects observed in the Rayleigh scatter of Mössbauer radiation and Mössbauer absorption spectroscopy may be ascribed to change in the intramolecular conformational mobility of proteins and not to the different types of motion of the macromolecule as a whole.
[Show abstract][Hide abstract] ABSTRACT: The dependence of the Mössbauer elastic scattering fraction on the hydration degree (h) has been studied for hydrated samples of human albumen (HSA), lysozyme and trypsin pancreatic inhibitor, within the range
ofh between 0–0.75 g H2O/g protein at 295 K, and for HSA with different hydration degrees (0.03, 0.25, 0.41, 0.65) in the temperature range between
100–320 K. An increase of the hydration degree forh>0.1 atT>200 K has been shown to result in the release of intramolecular mobility in proteins.
No preview · Article · Feb 1987 · Hyperfine Interactions
[Show abstract][Hide abstract] ABSTRACT: The authors have studied the dependence of the fraction of elastic scatter of Mössbauer radiation for wetted preparations of human serum albumin (h.s.a.), the pancreatic tryspin inhibitor and lysozyme in the interval of degrees of hydration h from 0 to 0·75 g H2O/g protein (T = 295 K) and in the temperature interval from 100 to 320 K for h.s.a. with different degrees of hydration (0·03, 0·25, 0·41 and 0·65). It is shown that with rise in the degree of hydration above h = 0·1 and for T > 200 K there is disinhibition of the intramolecular mobility in the proteins.
[Show abstract][Hide abstract] ABSTRACT: Specific features of the Rayleigh Scattering of Mössbauer Radiation (RSMR) technique in the study of biological systems are described. Experimental data show that the temperature and hydration degree are the principal parameters which influence intramolecular mobility in biopolymers. Data on temperature dependencies of elastic fraction, f, and spectrum line-shape do not fit neither Debye or Einstein models of solids nor the free diffusion in liquids and demand for their explanation a multimode approximation (i.e. a wide spectrum of correlation times, at T = 293 K from 10-6 s to 10-12-10-13 s). On the basis of RSMR, low temperature specific heat and X-ray dynamic analysis data and from the general conditions that information macromolecule must be in a non-equilibrium state (an independent confirmation of this fact comes from the kinetic model of protein folding) a glass-like dynamical model of biopolymers is formulated. A possible interpretation of RSMR data shows that fluctuatively prepared tunneling between quasiequilibrium positions (QEP) can prevail activated transitions up to a room temperature.