Species-specificity of the cohesin-dockerin interaction between Clostridium thermocellum and Clostridium cellulolyticum: prediction of specificity determinants of the dockerin domain.
The cross-species specificity of the cohesin-dockerin interaction, which defines the incorporation of the enzymatic subunits into the cellulosome complex, has been investigated. Cohesin-containing segments from the cellulosomes of two different species, Clostridium thermocellum and Clostridium cellulolyticum, were allowed to interact with cellulosomal (dockerin-containing) enzymes from each species. In both cases, the cohesin domain of one bacterium interacted with enzymes from its own cellulosome in a calcium-dependent manner, but the same cohesin failed to recognize enzymes from the other species. Thus, in the case of these two bacteria, the cohesin-dockerin interaction seems to be species-specific. Based on intra- and cross-species sequence comparisons among the different dockerins together with their known specificities, we tender a prediction as to the amino-acid residues critical to recognition of the cohesins. The suspected residues were narrowed down to only four, which comprise a repeated pair located within the calcium-binding motif of two duplicated sequences, characteristic of the dockerin domain. According to the proposed model, these four residues do not participate in the binding of calcium per se; instead, they appear to serve as recognition codes in promoting interaction with the cohesin surface.
Pagès
S
S
Centre National de la Recherche Scientifique, IBSM-IFR1, Marseille, France.
Bélaïch
A
A
Bélaïch
J P
JP
Morag
E
E
Lamed
R
R
Shoham
Y
Y
Bayer
E A
EA
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D002118:Calcium / Q000502:physiology; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics; D002482:Cellulose / Q000378:metabolism*; D003013:Clostridium / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D013045:Species Specificity
D001426:Bacterial Proteins; D002352:Carrier Proteins; C080369:CipA protein, Clostridium; C098847:CipC protein, Clostridium cellulolyticum; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D011994:Recombinant Proteins; C074074:cellulose binding protein A, Clostridium cellulovorans; D002482:Cellulose; D002118:Calcium