title: A general mechanism for competitor-induced dissociation of molecular complexes.
abstract: The kinetic stability of non-covalent macromolecular complexes controls many biological phenomena. Here we find that physical models of complex dissociation predict that competitor molecules will, in general, accelerate the breakdown of isolated bimolecular complexes by occluding rapid rebinding of the two binding partners. This prediction is largely independent of molecular details. We confirm the prediction with single-molecule fluorescence experiments on a well-characterized DNA strand dissociation reaction. Contrary to common assumptions, competitor-induced acceleration of dissociation can occur in biologically relevant competitor concentration ranges and does not necessarily imply ternary association of competitor with the bimolecular complex. Thus, occlusion of complex rebinding may play a significant role in a variety of biomolecular processes. The results also show that single-molecule colocalization experiments can accurately measure dissociation rates despite their limited spatiotemporal resolution.
authors.affiliation: 1] Department of Biochemistry, Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA [2] Materials Research Science and Engineering Center (MRSEC), Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA [3] Department of Physics, Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA.
authors.forename: Thayaparan
authors.initials: T
authors.lastname: Paramanathan
authors.affiliation: 1] Materials Research Science and Engineering Center (MRSEC), Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA [2] Department of Physics, Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Reeves
authors.affiliation: Department of Biochemistry, Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA.
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Friedman
authors.affiliation: 1] Materials Research Science and Engineering Center (MRSEC), Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA [2] Department of Physics, Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA.
authors.forename: Jane
authors.initials: J
authors.lastname: Kondev
authors.affiliation: 1] Department of Biochemistry, Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA [2] Materials Research Science and Engineering Center (MRSEC), Brandeis University, PO Box 549110, Waltham, Massachusetts 02454-9110, USA.
authors.forename: Jeff
authors.initials: J
authors.lastname: Gelles
mesh_terms: D007700:Kinetics; D046911:Macromolecular Substances / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008954:Models, Biological
chemical_list: D046911:Macromolecular Substances