@article{1299975,

title = {Dissecting the binding mode of low affinity phage display peptide ligands to protein targets by hydrogen/deuterium exchange coupled to mass spectrometry},

author = {Ulrike Leurs and Brian Lohse and Shonoi Ming and Philip A Cole and Rasmus P Clausen and Jesper L Kristensen and Kasper D Rand},

doi = {10.1021/ac503137u},

issn = {1520-6882},

year  = {2014},

date = {2014-12-01},

journal = {Anal Chem},

volume = {86},

number = {23},

pages = {11734-41},

abstract = {Phage display (PD) is frequently used to discover peptides capable of binding to biological protein targets. The structural characterization of peptide-protein complexes is often challenging due to their low binding affinities and high structural flexibility. Here, we investigate the use of hydrogen/deuterium exchange mass spectrometry (HDX-MS) to characterize interactions of low affinity peptides with their cognate protein targets. The HDX-MS workflow was optimized to accurately detect low-affinity peptide-protein interactions by use of ion mobility, electron transfer dissociation, nonbinding control peptides, and statistical analysis of replicate data. We show that HDX-MS can identify regions in the two epigenetic regulator proteins KDM4C and KDM1A that are perturbed through weak interactions with PD-identified peptides. Two peptides cause reduced HDX on opposite sides of the active site of KDM4C, indicating distinct binding modes. In contrast, the perturbation site of another PD-selected peptide inhibiting the function of KDM1A maps to a GST-tag. Our results demonstrate that HDX-MS can validate and map weak peptide-protein interactions and pave the way for understanding and optimizing the binding of peptide scaffolds identified through PD and similar ligand discovery approaches.},

keywords = {Binding Sites, Deuterium Exchange Measurement, Histone Demethylases, Humans, Jumonji Domain-Containing Histone Demethylases, Ligands, Mass Spectrometry, Models, Molecular, Molecular Structure, Peptides},

pubstate = {published},

tppubtype = {article}

}

@article{1299976,

title = {How IGF-1 activates its receptor},

author = {Jennifer M Kavran and Jacqueline M McCabe and Patrick O Byrne and Mary Katherine Connacher and Zhihong Wang and Alexander Ramek and Sarvenaz Sarabipour and Yibing Shan and David E Shaw and Kalina Hristova and Philip A Cole and Daniel J Leahy},

doi = {10.7554/eLife.03772},

issn = {2050-084X},

year  = {2014},

date = {2014-09-01},

journal = {Elife},

volume = {3},

abstract = {The type I insulin-like growth factor receptor (IGF1R) is involved in growth and survival of normal and neoplastic cells. A ligand-dependent conformational change is thought to regulate IGF1R activity, but the nature of this change is unclear. We point out an underappreciated dimer in the crystal structure of the related Insulin Receptor (IR) with Insulin bound that allows direct comparison with unliganded IR and suggests a mechanism by which ligand regulates IR/IGF1R activity. We test this mechanism in a series of biochemical and biophysical assays and find the IGF1R ectodomain maintains an autoinhibited state in which the TMs are held apart. Ligand binding releases this constraint, allowing TM association and unleashing an intrinsic propensity of the intracellular regions to autophosphorylate. Enzymatic studies of full-length and kinase-containing fragments show phosphorylated IGF1R is fully active independent of ligand and the extracellular-TM regions. The key step triggered by ligand binding is thus autophosphorylation.},

keywords = {Amino Acid Sequence, Animals, Conserved Sequence, HEK293 Cells, Humans, IGF Type 1, Insulin, Insulin-Like Growth Factor I, Ligands, Mice, Models, Molecular, Molecular Sequence Data, Mutation, Phosphorylation, Protein Binding, Protein Multimerization, Protein Structure, Receptor, Tertiary},

pubstate = {published},

tppubtype = {article}

}