Adhesion of bacterial exopolymers to alpha-FeOOH: inner-sphere complexation of phosphodiester groups.
Extracellular polymeric substances (EPS) constitute a heterogeneous mixture of polyelectrolytes that mediate biomineralization and bacterial adhesion and stabilize biofilm matrixes in natural and artificial environments. Although nucleic acids are exuded extracellularly and are purported to be required for biofilm formation, direct evidence of the active mechanism is lacking. EPS were extracted from both Bacillus subtilis (a gram-positive bacterium) and Pseudomonas aeruginosa (a gram-negative bacterium) and their interaction with the goethite (alpha-FeOOH) surface was studied using attenuated total internal reflection infrared spectroscopy. Correspondence between spectral data and quantum chemical calculations demonstrate that phosphodiester groups of nucleic acids mediate the binding of EPS to mineral surfaces. Our data indicate that these groups emerge from the EPS mixture to form monodentate complexes with Fe centers on the goethite (alpha-FeOOH) surface, providing an energetically stable bond for further EPS or cell adhesion.
Omoike
Anselm
A
Department of Soil, Water and Environmental Science, The University of Arizona, Tucson, Arizona 85721, USA.
Chorover
Jon
J
Kwon
Kideok D
KD
Kubicki
James D
JD
D000327:Adsorption; D001412:Bacillus subtilis / Q000737:chemistry; D001422:Bacterial Adhesion; D005109:Extracellular Matrix / Q000737:chemistry; D058085:Iron Compounds / Q000737:chemistry*; D008903:Minerals; D008958:Models, Molecular; D015394:Molecular Structure; D010755:Organophosphates / Q000737:chemistry*; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D011550:Pseudomonas aeruginosa / Q000737:chemistry; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
D058085:Iron Compounds; D008903:Minerals; D010755:Organophosphates; D011135:Polysaccharides, Bacterial; C094886:goethite