title: Reversible switching of fluorophore property based on intrinsic conformational transition of adenylate kinase during its catalytic cycle.
abstract: Adenylate kinase shows a conformational transition (OPEN and CLOSED forms) during substrate binding and product release to mediate the phosphoryl transfer between ADP and ATP/AMP. The protein motional characteristics will be useful to construct switching systems of fluorophore properties caused by the catalytic cycle of the enzyme. This paper demonstrates in situ reversible switching of a fluorophore property driven by the conformational transition of the enzyme. The pyrene-conjugated mutant adenylate kinase is able to switch the monomer/excimer emission property of pyrene on addition of ADP or P(1)P(5)-di(adenosine-5')pentaphosphate (Ap5A, a transition state analog). The observation under the dilute condition (~0.1 μM) indicates that the emission spectral change was caused by the motion of a protein molecule and not led by protein-protein interactions through π-π stacking of pyrene rings. The switching can be reversibly conducted by using hexokinase-coupling reaction. The fashion of the changes in emission intensities at various ligand concentrations is different between ADP, Mg(2+)-bound ADP, and Mg(2+)-bound Ap5A. The emission property switching is repeatable by a sequential addition of a substrate in a one-pot process. It is proposed that the property of a synthetic molecule on the enzyme surface is switchable in response to the catalytic cycle of adenylate kinase.
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), Ikoma, Nara 630-0192, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Fujii
authors.forename: Shun
authors.initials: S
authors.lastname: Hirota
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuo
mesh_terms: D000263:Adenylate Kinase / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D002384:Catalysis; D017931:DNA Primers; D005456:Fluorescent Dyes / Q000737:chemistry*; D011487:Protein Conformation; D013057:Spectrum Analysis
chemical_list: D017931:DNA Primers; D005456:Fluorescent Dyes; D000263:Adenylate Kinase