The stability and dimeric state of𝛽β-lactoglobulin(β-lg)can be dramatically affected by labeling the thiophilic agent to Cys121,whereas the underlining mechanism of such an effect is still unclear.We label a fluorescenceresonance-energy-βtransfer(FRET)pair of donor(1,5-IAEDANS)and acceptor(5-IAF)dyes to Cys121 of𝛽β-lg monomers to investigate the effect of bulky thiophilic modification on the structure and stability of𝛽β-lg.It is found that the modification dramatically destroys the native structure ofβ-lg and results in an obvious increase of the𝛼-helical content,coincident with the accumulation of non-native𝛼α-helical intermediates during its folding process.Importantly,the dimeric state of𝛽β-lg can still be reached whereas its dimerization rate decreases dramatically,allowing us to characterize the dimerization process using the FRET method based on a stoppedflow apparatus.Our results reveal that the dimerization process occurs before the completely folding of individual monomers,providing direct evidence on the cooperativity of folding and binding processes.
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机译：Biosensor of alkaline phosphatase based on non-fluorescent FRET of Eu3+-doped oxide nanoparticles and phosphorylated peptide labeled with cyanine dye
机译：Effects of enhancing soil organic carbon sequestration in the topsoil by fertilization on crop productivity and stability: Evidence from long-term experiments with wheat-maize cropping systems in China
