Structural adaptations in the specialized bacteriophage T4 co-chaperonin Gp31 expand the size of the Anfinsen cage.
The Gp31 protein from bacteriophage T4 functionally substitutes for the bacterial co-chaperonin GroES in assisted protein folding reactions both in vitro and in vivo. But Gp31 is required for the folding and/or assembly of the T4 major capsid protein Gp23, and this requirement cannot be satisfied by GroES. The 2.3 A crystal structure of Gp31 shows that its tertiary and quaternary structures are similar to those of GroES despite the existence of only 14% sequence identity between the two proteins. However, Gp31 shows a series of structural adaptations which will increase the size and the hydrophilicity of the "Anfinsen cage," the enclosed cavity within the GroEL/GroES complex that is the location of the chaperonin-assisted protein folding reaction.
Hunt
J F
JF
Howard Hughes Medical Institute and Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas 75235-9050, USA.
van der Vies
S M
SM
Henry
L
L
Deisenhofer
J
J
D000595:Amino Acid Sequence; D017122:Bacteriophage T4 / Q000737:chemistry*; D003461:Crystallography; D004926:Escherichia coli / Q000737:chemistry; D007091:Image Processing, Computer-Assisted; D008969:Molecular Sequence Data; D010802:Phylogeny; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D014764:Viral Proteins / Q000737:chemistry*
D014764:Viral Proteins; C063473:gene 31 protein, Enterobacteria phage T4