The Escherichia coli heat shock proteins GroEL and GroES modulate the folding of the beta-lactamase precursor.
AUTOR(ES)
Laminet, A A
RESUMO
One of the fundamental problems in biochemistry is the role of accessory proteins in the process of protein folding. The Escherichia coli heat shock protein complex GroEL/ES has been suggested to be a 'chaperonin' and be involved in both oligomer assembly as well as protein transport through the membrane. We show here that the folding of the purified precursor of beta-lactamase is inhibited by purified GroEL or the GroEL/ES complex with a stoichiometry of one particle per molecule of pre-beta-lactamase. Purified GroES alone has no effect on folding. After Mg2+ ATP addition folding resumes and the yield of active enzyme is higher than in the absence of GroEL or GroEL/ES. Unexpectedly, GroEL or GroEL/ES, when added to folded pre-beta-lactamase, lead to an apparent net 'unfolding', probably to a collapsed state of the protein, which can be reversed by the addition of Mg2+ ATP. The reversible and Mg2+ ATP-dependent association of GroEL/ES with non-native proteins might explain its postulated role in both protein transport and oligomer assembly.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=551958Documentos Relacionados
- Effects of mutations in heat-shock genes groES and groEL on protein export in Escherichia coli.
- The groES and groEL heat shock gene products of Escherichia coli are essential for bacterial growth at all temperatures.
- Induction of heat shock proteins DnaK, GroEL, and GroES by salt stress in Lactococcus lactis.
- Assembly of Both the Head and Tail of Bacteriophage Mu Is Blocked in Escherichia coli groEL and groES Mutants
- Increased expression and purification of soluble iron-regulatory protein 1 from Escherichia coli co-expressing chaperonins GroES and GroEL