Bacteriophage-encoded cochaperonins can substitute for Escherichia coli's essential GroES protein.
The Escherichia coli chaperonin machine is composed of two members, GroEL and GroES. The GroEL chaperonin can bind 10-15% of E. coli's unfolded proteins in one of its central cavities and help them fold in cooperation with the GroES cochaperonin. Both proteins are absolutely essential for bacterial growth. Several large, lytic bacteriophages, such as T4 and RB49, use the host-encoded GroEL in conjunction with their own bacteriophage-encoded cochaperonin for the correct assembly of their major capsid protein, suggesting a cochaperonin specificity for the in vivo folding of certain substrates. Here, we demonstrate that, when the cochaperonin of either bacteriophage T4 (Gp31) or RB49 (CocO) is expressed in E. coli, the otherwise essential groES gene can be deleted. Thus, it appears that, despite very little sequence identity with groES, the bacteriophage-encoded Gp31 and CocO proteins are capable of replacing GroES in the folding of E. coli's essential, housekeeping proteins.
Département de Biochimie Médicale, Centre Médicale Universitaire, Geneva, Switzerland. france.ballivet@medecine.unige.ch
France
F
Keppel
Monique
M
Rychner
Costa
C
Georgopoulos
D017122:Bacteriophage T4 / Q000378:metabolism*; D015139:Blotting, Southern; D015153:Blotting, Western; D018835:Chaperonin 10 / Q000378:metabolism*; D018833:Chaperonins / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D017510:Protein Folding; D011995:Recombination, Genetic; D013696:Temperature; D013997:Time Factors; D014764:Viral Proteins / Q000378:metabolism
D018835:Chaperonin 10; D014764:Viral Proteins; C063473:gene 31 protein, Enterobacteria phage T4; D018833:Chaperonins