Effects of ammonium sulfate on the unfolding and refolding of the variable and constant fragments of an immunoglobulin light chain.


Abstract

The equilibria and kinetics of unfolding and refolding by guanidine hydrochloride of the VL and CL fragments of a type kappa immunoglobulin light chain were studied in the presence of ammonium sulfate using circular dichroism and tryptophyl fluorescence at pH 7.5 and 25 degrees C. The unfolding equilibria of the VL and CL fragments were described in terms of the two-state transition. The midpoints of unfolding in the absence of ammonium sulfate were at 0.9 and 1.2 M guanidine hydrochloride for the CL and VL fragments respectively. The transition curves were shifted to higher concentrations of guanidine hydrochloride by 1.4 and 1.6 M for the CL and VL fragments, respectively, per mole of ammonium sulfate. Unfolding reactions of the VL and CL fragments in 3 M guanidine hydrochloride followed first-order kinetics, and the rate constants for the two proteins were both greatly decreased by the presence of ammonium sulfate. The refolding reaction of the CL fragment in 0.3 M guanidine hydrochloride consisted of two phases, and the rate constants were increased a little by the presence of ammonium sulfate. The refolding reaction of the VL fragment in 0.3 M guanidine hydrochloride followed first-order kinetics, and the rate was not affected by the presence of ammonium sulfate. These results showed that ammonium sulfate stabilizes the CL and VL fragments mainly by decreasing the unfolding rate. Study holds ProTherm entries: 3919, 3920, 3921 Extra Details: VL and CL fragments; two-state transition; transition curves;,first-order kinetics; rate constants

Submission Details

ID: tRgjcQf4

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:23 p.m.

Version: 1

Publication Details
Goto Y;Ichimura N;Hamaguchi K,Biochemistry (1988) Effects of ammonium sulfate on the unfolding and refolding of the variable and constant fragments of an immunoglobulin light chain. PMID:3130099
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 PDB Entries

Structure ID Release Date Resolution Structure Title
1AR2 1997-08-08T00:00:00+0000 2.8 DISULFIDE-FREE IMMUNOGLOBULIN FRAGMENT
1BWW 1998-09-29T00:00:00+0000 1.7 BENCE-JONES IMMUNOGLOBULIN REI VARIABLE PORTION, T39K MUTANT
1REI 1976-03-17T00:00:00+0000 2.0 THE MOLECULAR STRUCTURE OF A DIMER COMPOSED OF THE VARIABLE PORTIONS OF THE BENCE-JONES PROTEIN REI REFINED AT 2.0 ANGSTROMS RESOLUTION
1WTL 1994-06-08T00:00:00+0000 1.9 COMPARISON OF CRYSTAL STRUCTURES OF TWO HOMOLOGOUS PROTEINS: STRUCTURAL ORIGIN OF ALTERED DOMAIN INTERACTIONS IN IMMUNOGLOBULIN LIGHT CHAIN DIMERS
4L1H 2013-06-03T00:00:00+0000 1.68 Bence-Jones immunoglobulin REI variable portion with seven point mutations
5XP1 2017-05-31T00:00:00+0000 2.88 Structure of monomeric mutant of REI immunoglobulin light chain variable domain crystallized at pH 6
1EEQ 2000-02-01T00:00:00+0000 1.5 M4L/Y(27D)D/T94H Mutant of LEN
1EEU 2000-02-03T00:00:00+0000 1.6 M4L/Y(27D)D/Q89D/T94H mutant of LEN
1EFQ 2000-02-09T00:00:00+0000 1.6 Q38D mutant of LEN
1EK3 2000-03-06T00:00:00+0000 1.9 KAPPA-4 IMMUNOGLOBULIN VL, REC

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Immunoglobulin kappa variable 1D-33 P01593 KVD33_HUMAN
100.0 Immunoglobulin kappa variable 1D-33 P01594 KV133_HUMAN
99.0 Immunoglobulin kappa variable 4-1 P06312 KV401_HUMAN