Adhesion to cellulose by Ruminococcus albus: a combination of cellulosomes and Pil-proteins?
An obligatory step in cellulose degradation by anaerobic bacteria is the adhesion of the bacterium to the polysaccharide. In many anaerobic bacteria the adhesion protein, and the enzymes required for extensive polysaccharide hydrolysis, are organized into a complex and interesting structure called the cellulosome. The Gram-positive anaerobe Ruminococcus albus also produces a cellulosome-like complex, but the bacterium appears to possess other mechanism(s) for adhesion to plant surfaces and genes encoding functions relevant to growth on cellulose are conditionally expressed, as suggested by a combination of functional proteomics, differential display reverse-transcriptase PCR, and mutational analysis. A novel form of cellulose-binding protein has been identified and shown to belong to the Pil-protein family, being most similar to the type 4 fimbrial proteins of Gram-negative, pathogenic bacteria. These studies have provided new insights into the adhesion of bacteria to plant surfaces, and call attention to the likely existence of genetically analogous adhesion determinants in both pathogenic and non-pathogenic bacteria.
Morrison
M
M
Department of Animal Science, School of Biological Sciences, and Center for Biotechnology, University of Nebraska Lincoln, C220 Marvel Baker Hall, Lincoln, NE, USA. morrison.234@osu.edu
Miron
J
J
D018829:Adhesins, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002480:Cellulase / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D006095:Gram-Positive Cocci / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D015388:Organelles / Q000378:metabolism / Q000648:ultrastructure
D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; C115857:CbpC protein, Ruminococcus albus; D002482:Cellulose; D002480:Cellulase