title: Single-molecule lysozyme dynamics monitored by an electronic circuit.
abstract: Tethering a single lysozyme molecule to a carbon nanotube field-effect transistor produced a stable, high-bandwidth transducer for protein motion. Electronic monitoring during 10-minute periods extended well beyond the limitations of fluorescence techniques to uncover dynamic disorder within a single molecule and establish lysozyme as a processive enzyme. On average, 100 chemical bonds are processively hydrolyzed, at 15-hertz rates, before lysozyme returns to its nonproductive, 330-hertz hinge motion. Statistical analysis differentiated single-step hinge closure from enzyme opening, which requires two steps. Seven independent time scales governing lysozyme's activity were observed. The pH dependence of lysozyme activity arises not from changes to its processive kinetics but rather from increasing time spent in either nonproductive rapid motions or an inactive, closed conformation.
authors.affiliation: Institute for Surface and Interface Science, University of California Irvine, Irvine, CA 92697-2375, USA.
authors.forename: Yongki
authors.initials: Y
authors.lastname: Choi
authors.forename: Issa S
authors.initials: IS
authors.lastname: Moody
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Sims
authors.forename: Steven R
authors.initials: SR
authors.lastname: Hunt
authors.forename: Brad L
authors.initials: BL
authors.lastname: Corso
authors.forename: Israel
authors.initials: I
authors.lastname: Perez
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Weiss
authors.forename: Philip G
authors.initials: PG
authors.lastname: Collins
mesh_terms: D017122:Bacteriophage T4 / Q000201:enzymology; D055162:Biocatalysis; D004553:Electric Conductivity; D031541:Fluorescence Resonance Energy Transfer; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D018625:Microscopy, Atomic Force; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism*; D037742:Nanotubes, Carbon; D010457:Peptidoglycan / Q000378:metabolism; D011487:Protein Conformation; D011721:Pyrenes; D055672:Static Electricity; D013816:Thermodynamics; D014173:Transistors, Electronic
chemical_list: D037742:Nanotubes, Carbon; D010457:Peptidoglycan; D011721:Pyrenes; D009113:Muramidase