Insights into the structural determinants of cohesin dockerin specificity revealed by the crystal structure of the type II cohesin from Clostridium thermocellum SdbA

TY - JOUR

T1 - Insights into the structural determinants of cohesin dockerin specificity revealed by the crystal structure of the type II cohesin from Clostridium thermocellum SdbA

AU - Carvalho, A L

AU - Pires, V M R

AU - Gloster, T M

AU - Turkenburg, J P

AU - Prates, J A M

AU - Ferreira, L M A

AU - Romao, M J

AU - Davies, G J

AU - Fontes, C M G A

AU - Gilbert, H J

PY - 2005/6/24

Y1 - 2005/6/24

N2 - The plant cell wall degrading enzymes expressed by anaerobic microorganisms form large multienzyme complexes (cellulosomes). Cellulosomes assemble by the Type I dockerins on the catalytic subunits binding to the reiterated Type I cohesins in the molecular scaffold, while Type II dockerin-cohesin interactions anchor the complex onto the bacterial cell surface. Type I and Type II cohesin, dockerin pairs show no cross-specificity. Here we report the crystal structure of the Type II cohesin (CohII) from the Clostridium thermocellum cell surface anchoring protein SdbA. The protein domain contains nine beta-strands and a small a-helix. The beta-strands assemble into two elongated beta-sheets that display a typical jelly roll fold. The structure of CohII is very similar to Type I cohesins, and the dockerin binding site, which is centred at beta-strands 3, 5 and 6, is likely to be conserved in the two proteins. Subtle differences in the topology of the binding sites and a lack of sequence identity in the beta-strands that comprise the core of the dockerin binding site explain why Type I and Type II cohesins display such distinct specificities for their target dockerins. (c) 2005 Published by Elsevier Ltd.

AB - The plant cell wall degrading enzymes expressed by anaerobic microorganisms form large multienzyme complexes (cellulosomes). Cellulosomes assemble by the Type I dockerins on the catalytic subunits binding to the reiterated Type I cohesins in the molecular scaffold, while Type II dockerin-cohesin interactions anchor the complex onto the bacterial cell surface. Type I and Type II cohesin, dockerin pairs show no cross-specificity. Here we report the crystal structure of the Type II cohesin (CohII) from the Clostridium thermocellum cell surface anchoring protein SdbA. The protein domain contains nine beta-strands and a small a-helix. The beta-strands assemble into two elongated beta-sheets that display a typical jelly roll fold. The structure of CohII is very similar to Type I cohesins, and the dockerin binding site, which is centred at beta-strands 3, 5 and 6, is likely to be conserved in the two proteins. Subtle differences in the topology of the binding sites and a lack of sequence identity in the beta-strands that comprise the core of the dockerin binding site explain why Type I and Type II cohesins display such distinct specificities for their target dockerins. (c) 2005 Published by Elsevier Ltd.

KW - cohesin

KW - dockerin

KW - cellulosome

KW - cell-attachment

KW - plant cell wall

KW - PROTEIN CIPA

KW - CELLULOSOME

KW - DOMAIN

KW - RECOGNITION

KW - MODULE

KW - CELLULOLYTICUM

KW - SCAFFOLDIN

KW - PROVIDES

KW - COMPLEX

KW - ENZYMES

U2 - 10.1016/j.jmb.2005.04.037

DO - 10.1016/j.jmb.2005.04.037

M3 - Article

SN - 0022-2836

VL - 349

SP - 909

EP - 915

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

IS - 5

ER -