The cellulosomes: multienzyme machines for degradation of plant cell wall polysaccharides.
The discrete multicomponent, multienzyme cellulosome complex of anaerobic cellulolytic bacteria provides enhanced synergistic activity among the different resident enzymes to efficiently hydrolyze intractable cellulosic and hemicellulosic substrates of the plant cell wall. A pivotal noncatalytic subunit called scaffoldin secures the various enzymatic subunits into the complex via the cohesin-dockerin interaction. The specificity characteristics and tenacious binding between the scaffoldin-based cohesin modules and the enzyme-borne dockerin domains dictate the supramolecular architecture of the cellulosome. The diversity in cellulosome architecture among the known cellulosome-producing bacteria is manifest in the arrangement of their genes in either multiple-scaffoldin or enzyme-linked clusters on the genome. The recently described three-dimensional crystal structure of the cohesin-dockerin heterodimer sheds light on the critical amino acids that contribute to this high-affinity protein-protein interaction. In addition, new information regarding the regulation of cellulosome-related genes, budding genetic tools, and emerging genomics of cellulosome-producing bacteria promises new insight into the assembly and consequences of the multienzyme complex.
Bayer
Edward A
EA
Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel. Ed.Bayer@weizmann.ac.il
Belaich
Jean-Pierre
JP
Shoham
Yuval
Y
Lamed
Raphael
R
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins; D002473:Cell Wall / Q000378:metabolism; D044603:Cellulosomes / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone; D046973:Ruminiclostridium cellulolyticum / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D046974:Clostridium cellulovorans / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D010944:Plants / Q000378:metabolism*; D016415:Sequence Alignment; D000097722:Cohesins
D001426:Bacterial Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D005656:Fungal Proteins; D009687:Nuclear Proteins; D000097722:Cohesins; C074074:cellulose binding protein A, Clostridium cellulovorans