Reactivity of disulfide bonds is markedly affected by structure and environment: implications for protein modification and stability

Abstract

Disulfide bonds play a key role in stabilizing protein structures, with disruption strongly associated with loss of protein function and activity. Previous data have suggested that disulfides show only modest reactivity with oxidants. In the current study, we report kinetic data indicating that selected disulfides react extremely rapidly, with a variation of 104 in rate constants. Five-membered ring disulfides are particularly reactive compared with acyclic (linear) disulfides or six-membered rings. Particular disulfides in proteins also show enhanced reactivity. This variation occurs with multiple oxidants and is shown to arise from favorable electrostatic stabilization of the incipient positive charge on the sulfur reaction center by remote groups, or by the neighboring sulfur for conformations in which the orbitals are suitably aligned. Controlling these factors should allow the design of efficient scavengers and high-stability proteins. These data are consistent with selective oxidative damage to particular disulfides, including those in some proteins.

Chlorination and oxidation of the extracellular matrix protein laminin and basement membrane extracts by hypochlorous acid and myeloperoxidase

“…Both the MS and amino acid analyses indicate that Met residues are a major target for HOCl with this protein; this is in accord with the high rate constant for reaction of HOCl with this side-chain (k 3 ×10 7 -1 ×10 8 M −1 s −1 [23,75]. Cys and cystine are also highly reactive with HOCl [23,75,76], with k for Cys (typically) higher than for Met [75]. However, there is a very low abundance of Cys (but a moderate number of cystine) residues in laminin, and other ECM proteins in general, suggesting that these do not consume a significant amount of the HOCl provided.…”

A new in silico approach to investigate molecular aspects of factor IX missense causative mutations and their impact on the hemophilia B severity

“…More than 90% (49/54) of the mutations analyzed show differences compared to the WS in one or more of the following aspects: electrostatic pattern distribution, hydrophobicity, disulfide bonds disruption, and the number of calculated hydrogen bonds. The disulfide bond disruption is strongly associated with loss of protein function and activity (Karimi et al, ). In our work, it seems to be a crucial aspect in determining severe phenotype because all the 12 mutations causing this disruption leads to a severe HB.…”

Heat‐induced amyloid‐like aggregation of β‐lactoglobulin affected by glycation by α‐dicarbonyl compounds in a model study

“…24 The free -SH at Cys 121 of -LG is related to the formation of intermolecular disulfide bonds, which play a crucial role in the aggregation behavior of the protein. 25 In addition, there are three intermolecular disulfide bonds in -LG, and glycation could also occur in these Cys residues when disulfide exchange occur during heat treatment. Samples glycated by glucose appeared to share a similar decreasing trend to the control sample.…”