Protein folding: assignment of the energetic changes of reversible chemical modifications to the folded or unfolded states.


Abstract

Reversible chemical modifications of a series of single cysteine-containing variants of T4 lysozyme combined with thermal denaturation studies have been used to study the effects of these modifications on the stability of the protein. This allows dissection of the energetic effects of the modification on both the native and denatured states of this protein. At some sites modifications with various chemical reagents have essentially no effect on the stability of the protein, while at others, substantial changes in stability are observed. For example, chemical modification of cysteine at site 146 by cystamine (+NH3CH2CH2SSCH2-CH2NH3+) to form the mixed disulfide lowers the stability of the protein by about 1.1 kcal/mol. The reduction in the free energy of folding caused by the chemical modification is attributed to the destabilization of native state (0.9 kcal/mol), with only a relatively small effect from stabilization of the denatured state (0.2 kcal/mol). Chemical modifications of T4 lysozyme at site 146 with various chemical reagents show that the stability of the protein is lowered by a positively charged group and is relatively independent of the size of the side chains. This approach allows the investigation of the thermodynamic consequences of the reversible insertion of a wide variety of chemical entities at specific sites in proteins and, most importantly, allows dissection of the contribution of the chemical modifications to both the folded and unfolding states. It can be applied to almost any suitable macromolecular system. Study holds ProTherm entries: 5328, 5329, 5330, 5331, 5332, 5333, 5334, 5335, 5336, 5337, 5338 Extra Details: cysteine-free pseudo wild type lysozyme, (C54S, C97S) cysteine-containing variants; energetic effects;,chemical reagents; positively charged group

Submission Details

ID: yiMfxVjv3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:29 p.m.

Version: 1

Publication Details
Lu J;Baase WA;Muchmore DC;Dahlquist FW,Biochemistry (1992) Protein folding: assignment of the energetic changes of reversible chemical modifications to the folded or unfolded states. PMID:1510962
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
102L 1992-09-29T00:00:00+0000 1.74 HOW AMINO-ACID INSERTIONS ARE ALLOWED IN AN ALPHA-HELIX OF T4 LYSOZYME
103L 1992-09-29T00:00:00+0000 1.9 HOW AMINO-ACID INSERTIONS ARE ALLOWED IN AN ALPHA-HELIX OF T4 LYSOZYME
104L 1992-09-29T00:00:00+0000 2.8 HOW AMINO-ACID INSERTIONS ARE ALLOWED IN AN ALPHA-HELIX OF T4 LYSOZYME
107L 1992-12-17T00:00:00+0000 1.8 STRUCTURAL BASIS OF ALPHA-HELIX PROPENSITY AT TWO SITES IN T4 LYSOZYME
108L 1992-12-17T00:00:00+0000 1.8 STRUCTURAL BASIS OF ALPHA-HELIX PROPENSITY AT TWO SITES IN T4 LYSOZYME
109L 1992-12-17T00:00:00+0000 1.85 STRUCTURAL BASIS OF ALPHA-HELIX PROPENSITY AT TWO SITES IN T4 LYSOZYME
110L 1992-12-17T00:00:00+0000 1.7 STRUCTURAL BASIS OF ALPHA-HELIX PROPENSITY AT TWO SITES IN T4 LYSOZYME
111L 1992-12-17T00:00:00+0000 1.8 STRUCTURAL BASIS OF ALPHA-HELIX PROPENSITY AT TWO SITES IN T4 LYSOZYME
112L 1992-12-17T00:00:00+0000 1.8 STRUCTURAL BASIS OF ALPHA-HELIX PROPENSITY AT TWO SITES IN T4 LYSOZYME
113L 1992-12-17T00:00:00+0000 1.8 STRUCTURAL BASIS OF ALPHA-HELIX PROPENSITY AT TWO SITES IN T4 LYSOZYME

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Endolysin P00720 ENLYS_BPT4