Stability and folding of a mutant ribose-binding protein of Escherichia coli.
A mature mutant ribose-binding protein (RBP) of Escherichia coli was obtained by site-directed mutagenesis, replacing Thr-3 in the N-domain of wild-type mature RBP (WT-mRBP) with a Trp residue (N-Trp-mRBP). The equilibrium unfolding properties and the refolding kinetics of this protein were monitored by fluorescence and circular dichroism (CD). The stability of N-Trp-mRBP appears to be the same as that of C-Trp-mRBP, another mutant obtained by replacing Phe-187 with a Trp, and lower than that of WT-mRBP. The overall refolding rate of N-Trp-mRBP is much smaller than that of C-Trp-mRBP, which, in turn, is similar to that of WT-mRBP. For the case of WT-mRBP, the rate constant obtained by Tyr fluorescence is identical to the value obtained by CD. But with C-Trp-mRBP, the rate constant from CD is smaller than the value from the Trp fluorescence and this difference in the rate constants is much greater with the N-Trp-mRBP.
Kim
J S
JS
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yusong-Gu, Taejon, Korea.
Kim
H
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D002352:Carrier Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D009154:Mutation / Q000235:genetics; D033902:Periplasmic Binding Proteins; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000378:metabolism
D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D006146:Guanidines; D033902:Periplasmic Binding Proteins; C028003:RbsB protein, E coli; D014364:Tryptophan; D019791:Guanidine