TY - JOUR
T1 - The Clostridium cellulolyticum dockerin displays a dual binding mode for its cohesin partner
AU - Pinheiro, Benedita A.
AU - Proctor, Mark R.
AU - Martinez-Fleites, Carlos
AU - Prates, José A.M.
AU - Mon, Victoria A.
AU - Davies, Gideon J.
AU - Bayer, Edward A.
AU - Fontes, Carlos M.G.A.
AU - Fierobe, Henri Pierre
AU - Gilbert, Harry J.
N1 - Sem PDF conforme despacho.
Biotechnology and Biological Sciences Research Council BB/D522511/1.
PY - 2008/6/27
Y1 - 2008/6/27
N2 - The plant cell wall degrading apparatus of anaerobic bacteria includes a large multienzyme complex termed the "cellulosome." The complex assembles through the interaction of enzyme-derived dockerin modules with the multiple cohesin modules of the noncatalytic scaffolding protein. Here we report the crystal structure of the Clostridium cellulolyticum cohesin-dockerin complex in two distinct orientations. The data show that the dockerin displays structural symmetry reflected by the presence of two essentially identical cohesin binding surfaces. In one binding mode, visualized through the A16S/L17T dockerin mutant, the C-terminal helix makes extensive interactions with its cohesin partner. In the other binding mode observed through the A47S/F48T dockerin variant, the dockerin is reoriented by 180° and interacts with the cohesin primarily through the N-terminal helix. Apolar interactions dominate cohesin-dockerin recognition that is centered around a hydrophobic pocket on the surface of the cohesin, formed by Leu-87 and Leu-89, which is occupied, in the two binding modes, by the dockerin residues Phe-19 and Leu-50, respectively. Despite the structural similarity between the C. cellulolyticum and Clostridium thermocellum cohesins and dockerins, there is no cross-specificity between the protein partners from the two organisms. The crystal structure of the C. cellulolyticum complex shows that organism-specific recognition between the protomers is dictated by apolar interactions primarily between only two residues, Leu-17 in the dockerin and the cohesin amino acid Ala-129. The biological significance of the plasticity in dockerin-cohesin recognition, observed here in C. cellulolyticum and reported previously in C. thermocellum, is discussed.
AB - The plant cell wall degrading apparatus of anaerobic bacteria includes a large multienzyme complex termed the "cellulosome." The complex assembles through the interaction of enzyme-derived dockerin modules with the multiple cohesin modules of the noncatalytic scaffolding protein. Here we report the crystal structure of the Clostridium cellulolyticum cohesin-dockerin complex in two distinct orientations. The data show that the dockerin displays structural symmetry reflected by the presence of two essentially identical cohesin binding surfaces. In one binding mode, visualized through the A16S/L17T dockerin mutant, the C-terminal helix makes extensive interactions with its cohesin partner. In the other binding mode observed through the A47S/F48T dockerin variant, the dockerin is reoriented by 180° and interacts with the cohesin primarily through the N-terminal helix. Apolar interactions dominate cohesin-dockerin recognition that is centered around a hydrophobic pocket on the surface of the cohesin, formed by Leu-87 and Leu-89, which is occupied, in the two binding modes, by the dockerin residues Phe-19 and Leu-50, respectively. Despite the structural similarity between the C. cellulolyticum and Clostridium thermocellum cohesins and dockerins, there is no cross-specificity between the protein partners from the two organisms. The crystal structure of the C. cellulolyticum complex shows that organism-specific recognition between the protomers is dictated by apolar interactions primarily between only two residues, Leu-17 in the dockerin and the cohesin amino acid Ala-129. The biological significance of the plasticity in dockerin-cohesin recognition, observed here in C. cellulolyticum and reported previously in C. thermocellum, is discussed.
KW - THERMOCELLUM ENDOGLUCANASE CELD
KW - SCAFFOLDING PROTEIN CIPA
KW - X-RAY-SCATTERING
KW - CRYSTAL-STRUCTURE
KW - CELLULOSOME
KW - RECOGNITION
KW - SPECIFICITY
KW - DOMAIN
KW - DETERMINANTS
KW - DEGRADATION
UR - http://www.scopus.com/inward/record.url?scp=49649107283&partnerID=8YFLogxK
U2 - 10.1074/jbc.M801533200
DO - 10.1074/jbc.M801533200
M3 - Article
C2 - 18445585
AN - SCOPUS:49649107283
SN - 0021-9258
VL - 283
SP - 18422
EP - 18430
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 26
ER -