Structural Characterization of the pH-Denatured States of Ferricytochrome-c by Synchrotron Small Angle X-Ray Scattering

Cinelli, Stefania; Spinozzi, Francesco; Itri, Rosângela; Finet, Stéphanie; Carsughi, F.; Onori, G.; Mariani, Paolo

doi:10.1016/s0006-3495(01)75983-8

Cited by 47 publications

(52 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A significant increase in the percentage content of β-turn was observed in the spectrum of β-turn band and it exhibited 3cm -1 difference at 1685 cm -1 than that of the native state. This is in agreement with results reported by near UV CD (Goto et al, 1990;Qureshi et al, 2003), hydrogen exchange/2D NMR (Jeng et al, 1990), X-ray scattering (Cinelli et al, 2001). Conclusion: It has been observed that pH have affected ditrisbution of secondary structures.…”

Section: Resultssupporting

confidence: 92%

Secondary Structures Associated With Alkaline Transition of Horse Heart Ferricytochrome C: An FTIR Study

Wasagu¹,

Abubakar²,

Lawal³

et al. 2011

Nig J Bas App Sci

View full text Add to dashboard Cite

ABSTRACT:The spectra of amide I region (1700-1600cm -1 ) of horse heart ferricytochrome c at 20 o C are reported at low ionic strength at of pH values between 7.0 and 11.5 encompassing the alkaline transition. The mid-infrared spectra can probe the protein secondary structures. The Fourier transform infrared spectroscopic technique is used to investigate the changes in the conformationally sensitive amide I band of cytochrome c with pH and ionic strength. Analysis of these results supports the hypothesis that an increase in the non-repetitive secondary structure during alkaline transition is at the expense of regular secondary structures. These strongly suggest that structural switching and ligand exchange behaviour of ferricytochrome c is accompanied by conformational change in the protein backbone.

show abstract

Section: Resultssupporting

confidence: 92%

Secondary Structures Associated With Alkaline Transition of Horse Heart Ferricytochrome C: An FTIR Study

Wasagu¹,

Abubakar²,

Lawal³

et al. 2011

Nig J Bas App Sci

View full text Add to dashboard Cite

show abstract

“…For proteins unfolded by various denaturants or elevated temperatures, many studies have demonstrated that SAXS can be an effective tool to probe the global structure and the structure evolution even on a sub-millisecond scale (Chen et al, 1996;Segel et al, 1999;Doniach, 2001;Uzawa et al, 2004). Of the many SAXS studies on proteins structures, the majority seems to focus on the global size and the change in size of proteins in different solution conditions, with the local chain behavior discussed qualitatively using a Kratky-Porod plot and/or the pair distribution function p(r) (Cinelli et al, 2001). The size of the protein studied is often referred to the radius of gyration R g extracted from the corresponding SAXS data in the lowangle scattering region using the Guinier approximation.…”

Section: Introductionmentioning

confidence: 99%

Charge interaction and temperature effects on the solution structure of lysozyme as revealed by small-angle X-ray scattering

et al. 2007

View full text Add to dashboard Cite

We have studied the structure of lysozyme as influenced by solution environment using small‐angle X‐ray scattering (SAXS). With an ellipsoid form factor and a structure factor derived using the mean spherical approximation to account for the electrostatic repulsion of lysozyme, we have extracted detailed structural information about the protein in aqueous solutions, including the size, shape, and net charge number. The SAXS data analysis shows that lysozyme in pure water, expressing an averaged net charge number of ~6, folds to an ellipsoid‐like shape with a radius of gyration Rg = 16.6 Å. Temperature‐dependent SAXS for lysozyme in a buffer solution in which charge repulsion has been eliminated suggests that the protein may thermally unfold gradually along a preferred direction from the ellipsoidal shape with an aspect ratio of p≃ 2 at 303 K to an elongated shape with p≃ 3 at 343 K. The structural parameters of the unfolded lysozyme obtained using model fitting are compared with the envelope morphology simulated using a dummy‐residues model. From the evolution of the volume of lysozyme during the thermal unfolding process, we deduce a free‐energy profile for the protein thermally unfolded in water using a modified Ising model on the basis of a mean field approximation.

show abstract

“…We have further utilized SAS to investigate tranglutaminase thermal unfolding because the loss of protein native structure is usually reflected by an increase in the gyration radius (Cinelli et al 2001;Millet et al 2002). This occurs also in the case of denaturation of transglutaminase submitted to step-wise increase in temperature up to 70°C.…”

Section: Small-angle X-ray Scatteringmentioning

confidence: 99%

Effects of the regulatory ligands calcium and GTP on the thermal stability of tissue transglutaminase

et al. 2011

Self Cite

View full text Add to dashboard Cite

Tissue transglutaminase undergoes thermal inactivation with first-order kinetics at moderate temperatures, in a process which is affected in opposite way by the regulatory ligands calcium and GTP, which stabilize different conformations. We have explored the processes of inactivation and of unfolding of transglutaminase and the effects of ligands thereon, combining approaches of differential scanning calorimetry (DSC) and of thermal analysis coupled to fluorescence spectroscopy and small angle scattering. At low temperature (38-45°C), calcium promotes and GTP protects from inactivation, which occurs without detectable disruption of the protein structure but only local perturbations at the active site. Only at higher temperatures (52-56°C), the protein structure undergoes major rearrangements with alterations in the interactions between the N- and C-terminal domain pairs. Experiments by DSC and fluorescence spectroscopy clearly indicate reinforced and weakened interactions of the domains in the presence of GTP and of calcium, and different patterns of unfolding. Small angle scattering experiments confirm different pathways of unfolding, with attainment of limiting values of gyration radius of 52, 60 and 90 Å in the absence of ligands and in the presence of GTP and calcium. Data by X-rays scattering indicate that ligands influence retention of a relatively compact structure in the protein even after denaturation at 70°C. These results suggest that the complex regulation of the enzyme by ligands involves both short- and long-range effects which might be relevant for understanding the turnover of the protein in vivo.

show abstract

Structural Characterization of the pH-Denatured States of Ferricytochrome-c by Synchrotron Small Angle X-Ray Scattering

Cited by 47 publications

References 35 publications

Secondary Structures Associated With Alkaline Transition of Horse Heart Ferricytochrome C: An FTIR Study

Secondary Structures Associated With Alkaline Transition of Horse Heart Ferricytochrome C: An FTIR Study

Charge interaction and temperature effects on the solution structure of lysozyme as revealed by small-angle X-ray scattering

Effects of the regulatory ligands calcium and GTP on the thermal stability of tissue transglutaminase

Contact Info

Product

Resources

About