Skip to content
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
biochemistry, genetics and molecular biology
Stability of the domain interface contributes towards the catalytic function at the H-site of class alpha glutathione transferase A1-1
Biochimica et Biophysica Acta - Proteins and Proteomics, Volume 1804, No. 12, Year 2010
Notification
URL copied to clipboard!
Description
Cytosolic glutathione transferases (GSTs) are major detoxification enzymes in aerobes. Each subunit has two distinct domains and an active site consisting of a G-site for binding GSH and an H-site for an electrophilic substrate. While the active site is located at the domain interface, the role of the stability of this interface in the catalytic function of GSTs is poorly understood. Domain 1 of class alpha GSTs has a conserved tryptophan (Trp21) in helix 1 that forms a major interdomain contact with helices 6 and 8 in domain 2. Replacing Trp21 with an alanine is structurally non-disruptive but creates a cavity between helices 1, 6 and 8 thus reducing the packing density and van der Waals contacts at the domain interface. This results in destabilization of the protein and a marked reduction in catalytic activity. While functionality at the G-site is not adversely affected by the W21A mutation, the H-site becomes more accessible to solvent and less favorable for the electrophilic substrate 1-chloro-2,4-dinitrobenzene (CDNB). Not only does the mutation result in a reduction in the energy for stabilizing the transition state formed in the SNAr reaction between the substrates GSH and CDNB, it also compromises the ability of the enzyme to form and stabilize a transition state analogue (Meisenheimer complex) formed between GSH and 1,3,5-trinitrobenzene (TNB). The study demonstrates that the stability of the domain-domain interface plays a role in mediating the catalytic functionality of the active site, particularly the H-site, of class alpha GSTs. © 2010 Elsevier B.V.
Authors & Co-Authors
Balchin, David
South Africa, Johannesburg
University of the Witwatersrand
Fanucchi, Sylvia
South Africa, Johannesburg
University of the Witwatersrand
Achilonu, Ikechukwu Anthony
South Africa, Johannesburg
University of the Witwatersrand
Adamson, Roslin J.
South Africa, Johannesburg
University of the Witwatersrand
Burke, Jonathan P.
South Africa, Johannesburg
University of the Witwatersrand
Fernandes, Manuel A.
South Africa, Johannesburg
University of the Witwatersrand
Gildenhuys, Samantha
South Africa, Johannesburg
University of the Witwatersrand
Dirr, Heini W.
South Africa, Johannesburg
University of the Witwatersrand
Statistics
Citations: 21
Authors: 8
Affiliations: 1
Identifiers
Doi:
10.1016/j.bbapap.2010.09.003
ISSN:
15709639
Research Areas
Cancer