title: Monitoring the conformational changes of an intrinsically disordered peptide using a quartz crystal microbalance.
abstract: Intrinsically disordered peptides (IDPs) have recently garnered much interest because of their role in biological processes such as molecular recognition and their ability to undergo stimulus-responsive conformational changes. The block V repeat-in-toxin motif of the Bordetella pertussis adenylate cyclase is an example of an IDP that undergoes a transition from a disordered state to an ordered beta roll conformation in the presence of calcium ions. In solution, a C-terminal capping domain is necessary for this transition to occur. To further explore the conformational behavior and folding requirements of this IDP, we have cysteine modified three previously characterized constructs, allowing for attachment to the gold surface of a quartz crystal microbalance (QCM). We demonstrate that, while immobilized, the C-terminally capped peptide exhibits similar calcium-binding properties to what have been observed in solution. In addition, immobilization on the solid surface appears to enable calcium-responsiveness in the uncapped peptides, in contrast to the behavior observed in solution. This work demonstrates the power of QCM as a tool to study the conformational changes of IDPs immobilized on surfaces and has implications for a range of potential applications where IDPs may be engineered and used including protein purification, biosensors, and other bionanotechnology applications.
authors.affiliation: Department of Chemical Engineering, Columbia University, New York, New York, USA.
authors.forename: Oren
authors.initials: O
authors.lastname: Shur
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.forename: Donald M
authors.initials: DM
authors.lastname: Cropek
authors.forename: Scott
authors.initials: S
authors.lastname: Banta
mesh_terms: D000262:Adenylyl Cyclases / Q000737:chemistry; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry; D001886:Bordetella pertussis / Q000201:enzymology; D002942:Circular Dichroism; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D058525:Quartz Crystal Microbalance Techniques / Q000379:methods*; D015203:Reproducibility of Results
chemical_list: D001426:Bacterial Proteins; D010455:Peptides; D000262:Adenylyl Cyclases