Powering a burnt bridges Brownian ratchet: a model for an extracellular motor driven by proteolysis of collagen.
Biased diffusion of collagenase on collagen fibrils may represent the first observed adenosine triphosphate-independent extracellular molecular motor. The magnitude of force generated by the enzyme remains unclear. We propose a propulsion mechanism based on a burnt bridges Brownian ratchet model with a varying degree of coupling of the free energy from collagen proteolysis to the enzyme motion. When constrained by experimental observations, our model predicts 0.1 pN stall force for individual collagenase molecules. A dimer, surprisingly, can generate a force in the range of 5 pN, suggesting that the motor can be of biological significance.
Saffarian
Saveez
S
Cell Biology Department, Harvard Medical School/CBR, 200 Longwood Avenue, Boston, MA 02115, USA.
Qian
Hong
H
Collier
Ivan
I
Elson
Elliot
E
Goldberg
Gregory
G
D003094:Collagen / Q000737:chemistry* / Q000502:physiology*; D003198:Computer Simulation; D004548:Elasticity; D004735:Energy Transfer / Q000502:physiology; D045604:Extracellular Fluid / Q000737:chemistry / Q000502:physiology; D020781:Matrix Metalloproteinase 1 / Q000737:chemistry* / Q000502:physiology*; D008954:Models, Biological; D008956:Models, Chemical; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000502:physiology*; D009068:Movement / Q000502:physiology; D010447:Peptide Hydrolases / Q000737:chemistry / Q000502:physiology; D011485:Protein Binding; D013314:Stress, Mechanical; D014783:Viscosity
D020409:Molecular Motor Proteins; D003094:Collagen; D010447:Peptide Hydrolases; D020781:Matrix Metalloproteinase 1