Role of disulfide bonds in conformational stability and folding of 5′-deoxy-5′-methylthioadenosine phosphorylase II from the hyperthermophilic archaeon Sulfolobus solfataricus

2012 ◽  
Vol 1824 (10) ◽  
pp. 1136-1143 ◽  
Author(s):  
Giovanna Cacciapuoti ◽  
Francesca Fuccio ◽  
Luigi Petraccone ◽  
Pompea Del Vecchio ◽  
Marina Porcelli
Keyword(s):  
Disulfide Bonds ◽  
Conformational Stability ◽  
Sulfolobus Solfataricus ◽  
Hyperthermophilic Archaeon ◽  
Methylthioadenosine Phosphorylase

Thermal Unfolding of Nucleoside Hydrolases from the Hyperthermophilic Archaeon Sulfolobus solfataricus: Role of Disulfide Bonds

2012 ◽  
Vol 19 (3) ◽  
pp. 369-374 ◽  
Author(s):  
Marina Porcelli ◽  
Ester De Leo ◽  
Pompea Del Vecchio ◽  
Francesca Fuccio ◽  
Giovanna Cacciapuoti
Keyword(s):  
Disulfide Bonds ◽  
Sulfolobus Solfataricus ◽  
Thermal Unfolding ◽  
Hyperthermophilic Archaeon ◽  
Nucleoside Hydrolases

The Single Disulfide-Directed β-Hairpin Fold: Role of Disulfide Bond in Folding and Effect of an Additional Disulfide Bond on Stability

2020 ◽  
Vol 73 (4) ◽  
pp. 312
Author(s):  
Balasubramanyam Chittoor ◽  
Bankala Krishnarjuna ◽  
Rodrigo A. V. Morales ◽  
Raymond S. Norton
Keyword(s):  
Disulfide Bond ◽  
Disulfide Bonds ◽  
Solution Structure ◽  
Conformational Stability ◽  
Disulfide Bridge ◽  
Solution Nmr ◽  
Peptide Epitope ◽  
The Core ◽  
Native Fold

Disulfide bonds play a key role in the oxidative folding, conformational stability, and functional activity of many peptides. A few disulfide-rich peptides with privileged architecture such as the inhibitor cystine knot motif have garnered attention as templates in drug design. The single disulfide-directed β-hairpin (SDH), a novel fold identified more recently in contryphan-Vc1, has been shown to possess remarkable thermal, conformational, and chemical stability and can accept a short bioactive epitope without compromising the core structure of the peptide. In this study, we demonstrated that the single disulfide bond is critical in maintaining the native fold by replacing both cysteine residues with serine. We also designed an analogue with an additional, non-native disulfide bridge by replacing Gln1 and Tyr9 with Cys. Contryphan-Vc11–22[Q1C, Y9C] was synthesised utilising orthogonal cysteine protection and its solution structure determined using solution NMR spectroscopy. This analogue maintained the overall fold of native contryphan-Vc1. Previous studies had shown that the β-hairpin core of contryphan-Vc1 was resistant to proteolysis by trypsin and α-chymotrypsin but susceptible to cleavage by pepsin. Contryphan-Vc11–22[Q1C, Y9C] proved to be completely resistant to pepsin, thus confirming our design strategy. These results highlight the role of the disulfide bond in maintaining the SDH fold and provide a basis for the design of more stable analogues for peptide epitope grafting.

The role of disulfide bonds in the conformational stability and catalytic activity of phytase

2004 ◽  
Vol 82 (2) ◽  
pp. 329-334 ◽  
Author(s):  
Xiao-Yun Wang ◽  
Fan-Guo Meng ◽  
Hai-Meng Zhou
Keyword(s):  
Catalytic Activity ◽  
Disulfide Bonds ◽  
Conformational Stability ◽  
Three Dimensional ◽  
Fluorescence Emission ◽  
Dimensional Structure ◽  
Enzyme Activity Assay ◽  
First Order ◽  
Far Ultraviolet

Previous studies have predicted five disulfide bonds in Aspergillus niger phytase (phy A). To investigate the role of disulfide bonds, intrinsic fluorescence spectra, far-ultraviolet circular dichroism (CD) spectra, and an enzyme activity assay were used to compare the differences of catalytic activity and conformational stability of phytase during denaturation in urea in the presence and absence of dithiothreitol (DTT). In the presence of 2 mM DTT, the inactivation and unfolding were greatly enhanced at the same concentration of denaturant. The fluorescence emission maximum red shift and decreases of ellipticity at 222 nm were in accord with the changes of catalytic activity. The kinetics of the unfolding courses were a biphasic process consisting of two first-order reactions in the absence of DTT and a monophasic process of a first-order reaction in the presence of DTT. The results suggested that the loss of enzymatic activity was most likely because of a conformational change, and that disulfide bonds played an important role in three-dimensional structure and catalytic activity.Key words: phytase, urea denaturation, inactivation, disulfide bond.

scholarly journals An All-Atomistic Molecular Dynamics Study to Determine the Structural Importance of Disulfide Bonds in Immunoglobulin G and Bovine Serum Albumin

2018 ◽  
Vol 15 (1) ◽  
Author(s):  
Akshay Mathavan ◽  
Akash Mathavan ◽  
Michael Fortunato ◽  
Coray Colina
Keyword(s):  
Molecular Dynamics ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Immunoglobulin G ◽  
Bovine Serum ◽  
Disulfide Bonds ◽  
Structural Changes ◽  
Conformational Stability ◽  
The Stability

A fully-atomistic molecular dynamics study was performed to determine the importance of disulfide bonds on the stability of immunoglobulin G (IgG) and bovine serum albumin (BSA).The transferability of a previous prescreening methodology to assess contributions from individual disulfide bonds on conformational stability was tested on both proteins. In IgG, it was apparent that inter-chain and intra-chain disulfide bonds play different roles in maintaining structure, evidenced by clear separation of inter-chain cysteine residues upon cleavage of disulfide bonds. In BSA, a set of double disulfide bonds required both to be broken in order to observe significant structural changes, equivalently seen in a previous study of human serum albumin (HSA), a structurally similar protein. Structural analysis of IgG showed deviations in distances between domains, while analysis of BSA suggested more local structural changes. This work helps confirm the efficacy and reproducibility of the prescreening methodology on both a novel, larger protein such as IgG and a more homologous (to HSA), globular protein such as BSA. The results provide insight into the role of specific disulfide bonds in the stability of IgG and BSA. KEYWORDS: Molecular Dynamics; Atomistic Simulations; Immunoglobulin G; Bovine Serum Albumin; Disulfide Bonds

scholarly journals Role of Disulfide Bridges in the Activity and Stability of a Cold-Active α-Amylase

2005 ◽  
Vol 187 (17) ◽  
pp. 6206-6212 ◽  
Author(s):  
Khawar Sohail Siddiqui ◽  
Anne Poljak ◽  
Michael Guilhaus ◽  
Georges Feller ◽  
Salvino D'Amico ◽  
...  
Keyword(s):  
Active Site ◽  
Disulfide Bonds ◽  
Conformational Stability ◽  
Iodoacetic Acid ◽  
Mass Spectrometry Analysis ◽  
Stable Region ◽  
Disulfide Bridges ◽  
Activity Increase ◽  
Spectrometry Analysis

ABSTRACT The cold-adapted α-amylase from Pseudoalteromonas haloplanktis unfolds reversibly and cooperatively according to a two-state mechanism at 30°C and unfolds reversibly and sequentially with two transitions at temperatures below 12°C. To examine the role of the four disulfide bridges in activity and conformational stability of the enzyme, the eight cysteine residues were reduced with β-mercaptoethanol or chemically modified using iodoacetamide or iodoacetic acid. Matrix-assisted laser desorption-time of flight mass spectrometry analysis confirmed that all of the cysteines were modified. The iodoacetamide-modified enzyme reversibly folded/unfolded and retained approximately one-third of its activity. Removal of all disulfide bonds resulted in stabilization of the least stable region of the enzyme (including the active site), with a concomitant decrease in activity (increase in activation enthalpy). Disulfide bond removal had a greater impact on enzyme activity than on stability (particularly the active-site region). The functional role of the disulfide bridges appears to be to prevent the active site from developing ionic interactions. Overall, the study demonstrated that none of the four disulfide bonds are important in stabilizing the native structure of enzyme, and instead, they appear to promote a localized destabilization to preserve activity.

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