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Lanthanide binding and IgG affinity construct: Potential applications in solution NMR, MRI, and luminescence microscopy
Author(s) -
Barb Adam W.,
Ho Tienhuei Grace,
FlanaganSteet Heather,
Prestegard James H.
Publication year - 2012
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.2133
Subject(s) - luminescence , lanthanide , microscopy , chemistry , nuclear magnetic resonance , crystallography , biophysics , materials science , nanotechnology , physics , biology , optics , optoelectronics , organic chemistry , ion
Abstract Paramagnetic lanthanide ions when bound to proteins offer great potential for structural investigations that utilize solution nuclear magnetic resonance spectroscopy, magnetic resonance imaging, or optical microscopy. However, many proteins do not have native metal ion binding sites and engineering a chimeric protein to bind an ion while retaining affinity for a protein of interest represents a significant challenge. Here we report the characterization of an immunoglobulin G‐binding protein redesigned to include a lanthanide binding motif in place of a loop between two helices (Z‐L2LBT). It was shown to bind Tb 3+ with 130 n M affinity. Ions such as Dy 3+ , Yb 3+ , and Ce 3+ produce paramagnetic effects on NMR spectra and the utility of these effects is illustrated by their use in determining a structural model of the metal‐complexed Z‐L2LBT protein and a preliminary characterization of the dynamic distribution of IgG Fc glycan positions. Furthermore, this designed protein is demonstrated to be a novel IgG‐binding reagent for magnetic resonance imaging (Z‐L2LBT:Gd 3+ complex) and luminescence microscopy (Z‐L2LBT: Tb 3+ complex).