We make progress in the structural study of cellulosome dockerin

[2014.9.28] Cellulososme is a multi-enzyme complex assembled by cohesin and dockerin modules. The cellulase Cel48S is the most abundant enzyme in cellulosome of Clostridium thermocellum. The solution structure of the dockerin module of Cel48S (Doc48S) was determined by double resonance NMR method in 2001, and the solution structure displayed substantial conformational differences from subsequent structures of dockerin modules in complex with their cognate cohesin modules, raising the question whether the source of the observed differences resulted from cohesin-induced structural rearrangements. We re-determined the solution structure of Doc48S using 15N-, 13C-labelled protein and triple resonance methods. The structure adopted a fold similar to X-ray crystal structures of dockerin modules in complex with their cohesin partners. A unique cis-peptide bond between Leu-65 and Pro-66 in the Cel48S type-I dockerin module was also identified in the present structure. Our structural analysis of the Cel48S type-I dockerin module indicates that it does not undergo appreciable cohesin-induced structural alterations but rather assumes an inherent calcium-dependent cohesin-primed conformation.

The paper was published on J. Struct. Biol. The Ph.D. candidate Chao Chen is the first author, and Prof. Yingang Feng is the corresponding author. Prof. Steven P. Smith from Queen’s University Canada, Prof. Raphael Lamed from Tel Aviv University Israel, and Prof. Edward A. Bayer from The Weizmann Institute of Science Israel paticipated in the research. The work was supported by the 973 program and NNSFC.

NCBI PubMed 

Chao Chen, Zhenling Cui, Yan Xiao, Qiu Cui, Steven P. Smith, Raphael Lamed, Edward A. Bayer and Yingang Feng* (2014) Revisiting the NMR solution structure of the Cel48S type-I dockerin module from Clostridium thermocellum reveals a cohesin-primed conformation. J. Struct. Biol. 188(2), 188-193. [Full text (Publisher website)]