Thermodynamics of thermal and athermal denaturation of gamma-crystallins: changes in conformational stability upon glutathione reaction.


Abstract

The conformational stabilities of bovine lens gamma-crystallin fractions II, IIIA, IIIB, and IVA and those modified with glutathione were compared by studying the thermal and guanidine hydrochloride (Gdn-HCl) denaturation behavior. The conformational state was monitored by both far-UV CD and fluorescence measurements. All the gamma-crystallins studied showed a sigmoidal order-disorder transition with varied melting temperatures. The thermal denaturation of these proteins is reversible up to a temperature 3 or 4 degrees C above T 1/2; above this temperature, irreversible aggregation occurs. The validity of a two-state approximation of both thermal and Gdn-HCl denaturation was tested for all four crystallins, and the presence of one or more intermediates was evident in the unfolding of IVA. delta GDH2O values of these crystallins range from 4 to 9 kcal/mol. Upon glutathione treatment IVA showed the maximum decrease in T 1/2 by approximately 9 degrees C and in delta GDH2O value by 29%; the smallest decrease in T 1/2 was for IIIA by 2 degrees C and in delta GDH2O by 15%. We have demonstrated that the glutathione reaction can dramatically reduce the conformational stability of gamma-crystallins and, thus, that the thermodynamic quantities of the unreacted crystallins can be used to evaluate the stability of these proteins when modified during cataract formation. Study holds ProTherm entries: 3696, 3697, 3698, 3699, 3700, 3701, 3702, 3703, 3704, 3705, 3706, 3707 Extra Details: glutathione reaction; sigmoidal order-disorder transition;,two-state approximation; unreacted crystallins

Submission Details

ID: 7z6L8QJy3

Submitter: Connie Wang

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

Version: 1

Publication Details
Kono M;Sen AC;Chakrabarti B,Biochemistry (1990) Thermodynamics of thermal and athermal denaturation of gamma-crystallins: changes in conformational stability upon glutathione reaction. PMID:2302385
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
1AMM 1996-11-08 1.2 1.2 ANGSTROM STRUCTURE OF GAMMA-B CRYSTALLIN AT 150K
4W9B 2015-09-09 1.28 Crystal structure of Gamma-B Crystallin expressed in E. coli based on mRNA variant 1
4W9A 2015-09-09 1.38 Crystal structure of Gamma-B Crystallin expressed in E. coli based on mRNA variant 2
4GCR 1993-10-31 1.47 STRUCTURE OF THE BOVINE EYE LENS PROTEIN GAMMA-B (GAMMA-II)-CRYSTALLIN AT 1.47 ANGSTROMS
1DSL 1996-07-11 1.55 GAMMA B CRYSTALLIN C-TERMINAL DOMAIN
1GCS 1994-04-30 2.0 STRUCTURE OF THE BOVINE GAMMA-B CRYSTALLIN AT 150K
1I5I 2001-03-07 2.4 THE C18S MUTANT OF BOVINE (GAMMA-B)-CRYSTALLIN
1GAM 1996-07-11 2.6 GAMMA B CRYSTALLIN TRUNCATED C-TERMINAL DOMAIN

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
92.0 Gamma-crystallin B P10066 CRGB_RAT
94.9 Gamma-crystallin B A3RLE1 CRGB_CANLF
100.0 Gamma-crystallin B P02526 CRGB_BOVIN