ISSN:
1574-6941
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Many thermophilic bacteria belong to groups with deep phylogenetic lineages and ancestral forms were established before the occurrence of eucaryotes that produced cellulose and hemicellulose. Thus they may have acquired their β-glycanase genes from more recent mesophilic bacteria. Most research has focussed on extremely thermophilic eubacteria growing above 65°C under anaerobic conditions. Only recently have aerobic cellulolytic thermophiles been described from widely separated lineages (for example, Rhodothermus marinus, Caldibacillus cellulovorans). Many thermophilic bacteria produce cellulases and xylanases that have novel structures, with additional protein domains not identified with their catalytic activity. Many of these enzymes are multifunctional and code for more than one catalytic activity. This type of enzyme structure was first identified in the extreme thermophile Caldicellulosiruptor saccharolyticus. There is a general relatedness evident between catalytic domains, cellulose binding domains and other ancillary domains, which suggests that there may have been significant lateral gene transfer in the evolution of these microorganisms. Detailed molecular studies show that there is variation in the sequences of these related but not identical genes from taxonomically widely-separated organisms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-6941.1999.tb00565.x
Permalink