| Literature DB >> 18402443 |
W Paige Hall1, Jeffrey N Anker, Yao Lin, Justin Modica, Milan Mrksich, Richard P Van Duyne.
Abstract
A plasmonic switch based on the calcium-induced conformational changes of calmodulin is shown to exhibit reversible wavelength modulations in response to changing calcium concentration. The extinction maximum (lambdamax) of a localized surface plasmon resonance (LSPR) sensor functionalized with a novel calmodulin construct, cutinase-calmodulin-cutinase (CutCaMCut), reversibly shifts by 2-3 nm. A high-resolution (HR) LSPR spectrometer with a wavelength resolution (3sigma) of 1.5 x 10-2 nm was developed to detect these wavelength modulations in real-time, providing information about the dynamics and structure of the protein. The rate of conversion from open (Ca2+-bound) to closed (Ca2+-free) calmodulin is shown to be 4-fold faster than the reverse process, with a closing rate of 0.127 s-1 and opening rate of 0.034 s-1. As far as we are aware, this plasmonic switch marks the first use of LSPR spectroscopy to detect reversible conformational changes in an unlabeled protein.Entities:
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Year: 2008 PMID： 18402443 PMCID： PMC2723789 DOI： 10.1021/ja7109037
Source DB: PubMed Journal: J Am Chem Soc ISSN： 0002-7863 Impact factor: 15.419