title: Investigating the specific interactions between carbonic anhydrase and a sulfonamide inhibitor by single-molecule force spectroscopy.
abstract: In this communication, we report on the interaction landscape of an active site-specific enzyme-inhibitor complex by single-molecule force spectroscopy. Electrostatic immobilization was employed to orient a carbonic anhydrase enzyme on a positively charged surface so its active site is pointing upward. This approach to immobilization effectively increases the number of specific interactions measured between the zinc ion of the active site on carbonic anhydrase and a sulfonamide inhibitor tethered to an atomic force microscope (AFM) probe. Further, it reduces the time required for data collection and thereby minimizes the possible mechanical damage to the probe and contamination of the enzyme surface. The rupture force measured at various loading rates is interpreted in terms of a single energy barrier for the carbonic anhydrase enzyme-sulfonamide inhibitor complex from which the kinetic and thermodynamic parameters were estimated on the basis of microscopic models and were compared to the Bell-Evans model. The dissociation rate for the enzyme-inhibitor complex was found to be significantly faster (~35 times) than the natural spontaneous dissociation rate.
authors.affiliation: Department of Chemistry & Biochemistry, Calvin College, Grand Rapids, MI 49546, USA.
authors.forename: Sarah G
authors.initials: SG
authors.lastname: Kamper
authors.forename: Laura
authors.initials: L
authors.lastname: Porter-Peden
authors.forename: Ronald
authors.initials: R
authors.lastname: Blankespoor
authors.forename: Kumar
authors.initials: K
authors.lastname: Sinniah
authors.forename: Dejian
authors.initials: D
authors.lastname: Zhou
authors.forename: Chris
authors.initials: C
authors.lastname: Abell
authors.forename: Trevor
authors.initials: T
authors.lastname: Rayment
mesh_terms: D001665:Binding Sites; D002257:Carbonic Anhydrase Inhibitors / Q000737:chemistry* / Q000494:pharmacology; D002256:Carbonic Anhydrases / Q000737:chemistry* / Q000187:drug effects; D007700:Kinetics; D018625:Microscopy, Atomic Force / Q000379:methods*; D015394:Molecular Structure; D013449:Sulfonamides / Q000737:chemistry* / Q000494:pharmacology; D013816:Thermodynamics
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D013449:Sulfonamides; D002256:Carbonic Anhydrases