Structural insights into the mechanism of formation of cellulosomes probed by small angle X-ray scattering.
Exploring the mechanism by which the multiprotein complexes of cellulolytic organisms, the cellulosomes, attain their exceptional synergy is a challenge for biologists. We have studied the solution structures of the Clostridium cellulolyticum cellulosomal enzyme Cel48F in the free and complexed states with cohesins from Clostridium thermocellum and Clostridium cellulolyticum by small angle x-ray scattering in order to investigate the conformational events likely to occur upon complexation. The solution structure of the free cellulase indicates that the dockerin module is folded, whereas the linker connecting the catalytic module to the dockerin is extended and flexible. Remarkably, the docking of the different cohesins onto Cel48F leads to a pleating of the linker. The global structure determined here allowed modeling of the atomic structure of the C. cellulolyticum dockerin-cohesin interface, highlighting the local differences between both organisms responsible for the species specificity.
Hammel
Michal
M
Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS and Universités d'Aix-Marseille I and II, 31 Chemin Joseph Aiguier, F-13402 Marseille cedex 20, France.
Fierobe
Henri-Pierre
HP
Czjzek
Mirjam
M
Finet
Stéphanie
S
Receveur-Bréchot
Véronique
V
D000595:Amino Acid Sequence; D002384:Catalysis; D044603:Cellulosomes / Q000737:chemistry*; D046973:Ruminiclostridium cellulolyticum / Q000378:metabolism; D048013:Acetivibrio thermocellus / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D012542:Scattering, Radiation; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014965:X-Rays
D011994:Recombinant Proteins