Chemical modification of tryptophan residues and stability changes in proteins.


The role of tryptophan residues in the stability of proteins was studied by ozone oxidation, which causes a small change in the tryptophan side chain. Trp 187 of the constant fragment of a type lambda immunoglobulin light chain, Trp 59 of ribonuclease T1, and Trp 62 of hen egg white lysozyme were oxidized specifically by ozone to N'-formylkynurenine or kynurenine. Judging from their circular dichroic and fluorescence spectra, these modified proteins were found to be the same as those of the respective intact proteins. However, even the slight modification of a single tryptophan residue produced a large decrease in the stability of these proteins to guanidine hydrochloride and heat. The smaller the extent of exposure of the tryptophan residue, the greater the effect of the modification on the stability. The formal kinetic mechanism of unfolding and refolding by guanidine hydrochloride of the CL fragment was not altered by tryptophan oxidation, but the rate constants for unfolding and refolding changed. The thermal unfolding transitions were analyzed to obtain the thermodynamic parameters. The enthalpy and entropy changes for the modified proteins were larger than the respective values for the intact proteins. Study holds ProTherm entries: 3670, 3671, 3672 Extra Details: tryptophan; ozone oxidation; kinetic mechanism;,thermodynamic parameters

Submission Details

ID: v3NpVwMu3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:22 p.m.

Version: 1

Publication Details
Okajima T;Kawata Y;Hamaguchi K,Biochemistry (1990) Chemical modification of tryptophan residues and stability changes in proteins. PMID:2125474
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Lysozyme C P00698 LYSC_CHICK
96.9 Lysozyme C P00700 LYSC_COLVI
96.9 Lysozyme C P00699 LYSC_CALCC
96.9 Lysozyme C Q7LZQ0 LYSC_CATWA
96.9 Lysozyme C Q7LZP9 LYSC_LOPIM
96.1 Lysozyme C Q7LZI3 LYSC_TRASA
95.3 Lysozyme C P00701 LYSC_COTJA
96.1 Lysozyme C P19849 LYSC_PAVCR
95.3 Lysozyme C P22910 LYSC_CHRAM
95.3 Lysozyme C Q7LZT2 LYSC_TRATE
95.2 Lysozyme C P00703 LYSC_MELGA
92.2 Lysozyme C P00704 LYSC_NUMME
93.0 Lysozyme C P24364 LYSC_LOPLE
94.6 Lysozyme C P24533 LYSC_SYRRE
93.2 Lysozyme C P00702 LYSC_PHACO
93.0 Lysozyme C P81711 LYSC_SYRSO
92.3 Lysozyme C P49663 LYSC_PHAVE