title: Electron microscopy of Bacillus subtilis GroESL chaperonin and interaction with the bacteriophage phi 29 head-tail connector.
abstract: The Bacillus subtilis GroESL chaperonin was isolated by sucrose density gradient centrifugation and the constituent GroES and GroEL moieties were purified by electrophoresis in agarose. Electron microscopic images of negatively stained GroEL and GroES oligomers and GroESL complexes were averaged using a reference-free alignment method. The GroEL and GroES particles had the sevenfold symmetry characteristic of their Escherichia coli counterparts. GroESL complexes, reconstituted efficiently in vitro from GroEL and GroES in the absence of added ADP or ATP, had the characteristic bullet- and football-like shapes in side view. Purified bacteriophage phi 29 head-tail connectors having a mass in excess of 0.4 MDa were shown to bind to GroESL at the end opposite to the GroES. The same GroESL-connector complexes were isolated from phage-infected cells in which capsid assembly was blocked, and thus the complex may have functional significance in phi 29 morphogenesis.
authors.affiliation: Department of Cell Biology, University of Minnesota, Minneapolis 55455, USA.
authors.forename: V
authors.initials: V
authors.lastname: Tsuprun
authors.forename: B S
authors.initials: BS
authors.lastname: Rajagopal
authors.forename: D
authors.initials: D
authors.lastname: Anderson
mesh_terms: D017103:Bacillus Phages / Q000737:chemistry* / Q000235:genetics; D001412:Bacillus subtilis / Q000737:chemistry* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D002213:Capsid / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D036022:Capsid Proteins; D018835:Chaperonin 10 / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D018834:Chaperonin 60 / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D018833:Chaperonins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D007091:Image Processing, Computer-Assisted; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D016624:Negative Staining; D011993:Recombinant Fusion Proteins / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins; D036022:Capsid Proteins; D018835:Chaperonin 10; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; C028715:GroE protein, E coli; C097970:GroESL protein, Bacteria; D006360:Heat-Shock Proteins; D046911:Macromolecular Substances; D011993:Recombinant Fusion Proteins; C097975:portal protein, bacteriophage phi29; D018833:Chaperonins