scholarly journals Isolation of isoform-specific binding proteins (Affimers) by phage display using negative selection

2017 ◽  
Vol 10 (505) ◽  
pp. eaan0868 ◽  
Author(s):  
Anna Ah-San Tang ◽  
Christian Tiede ◽  
David J. Hughes ◽  
Michael J. McPherson ◽  
Darren C. Tomlinson
2004 ◽  
Vol 18 (2) ◽  
pp. 237-249
Author(s):  
Nicholas J. Skelton ◽  
Michelle L. Schaffer ◽  
Kurt Deshayes ◽  
Tamas Blandl ◽  
Steven Runyon ◽  
...  

Insulin–like growth factor–I (IGF–I) is a central mediator of cell growth, differentiation and metabolism. Structural characterization of the protein has been hampered by a combination of internal dynamics and self–association that prevent crystallization and produce broad NMR resonances. To better characterize the functions of IGF–I, we have used phage display to identify peptides that antagonize the binding of IGF–I to its plasma binding proteins (IGFBPs) and cell–surface receptor (IGF–R). Interestingly, binding of peptide improves dramatically the quality of the NMR resonances of IGF–I, and enables the use of triple–resonance NMR methods to characterize the complexes. One such peptide, designated IGF–F1–1, has been studied in detail. In the complex, the peptide retains the same loop–helix motif seen in the free state whilst IGF–I contains three helices, as has been seen previously in low–resolution structures in the absence of ligand. The peptide binds at a hydrophobic patch between helix 1 and 3, a site identified previously by mutagenesis as a contact site for IGFBP1. Thus, antagonism of IGFBP1 binding exhibited by the peptide occurs by a simple steric occlusion mechanism. Antagonism of IGF–R binding may also be explained by a similar mechanism if receptor binding occurs by a two–site process, as has been postulated for insulin binding to its receptor. Comparisons with crystallographic structures determined for IGF–I in other complexes suggest that the region around helix 1 of IGF–I is conformationally conserved whereas the region around helix 3 adopts several different ligand–induced conformations. The ligand–induced structural variability of helix 3 appears to be a common feature across the insulin super–family. In the case of IGF–I, exchange between such conformations may be the source of the dynamic nature of free IGF–I, and likely has functional significance for the ability of IGF–I to recognize two signaling receptors and six binding proteins with high affinity.


2015 ◽  
Vol 6 (10) ◽  
pp. 5586-5594 ◽  
Author(s):  
Andrea E. Rawlings ◽  
Jonathan P. Bramble ◽  
Anna A. S. Tang ◽  
Lori A. Somner ◽  
Amy E. Monnington ◽  
...  

Biopanning was used to generate novel artificial binding proteins which are able to control the formation of synthetic cubic nanoparticles of magnetite.


1991 ◽  
Vol 11 (4) ◽  
pp. 2319-2323 ◽  
Author(s):  
J S Doctor ◽  
F M Hoffmann ◽  
B B Olwin

As assessed by competitive binding and protein-crosslinking experiments, Drosophila melanogaster cells possess basic fibroblast growth factor (bFGF)-specific binding proteins that are similar to FGF receptors on vertebrate cells in molecular weight and binding affinity; these D. melanogaster cells, however, have no detectable binding proteins for acidic fibroblast growth factor (aFGF). Consistent with the presence of bFGF-specific binding proteins, D. melanogaster cells degrade bFGF but not aFGF. These results indicate the conservation of heparin-binding growth factors and receptors between vertebrates and D. melanogaster.


1991 ◽  
Vol 130 (3) ◽  
pp. 469-NP ◽  
Author(s):  
S. C. Davies ◽  
J. A. H. Wass ◽  
R. J. M. Ross ◽  
A. M. Cotterill ◽  
C. R. Buchanan ◽  
...  

ABSTRACT The insulin-like growth factors (IGF-I and IGF-II) are almost completely bound in the circulation to specific binding proteins (IGFBPs). These IGFBPs appear to play a pivotal role in maintaining circulating levels and modulating the delivery of the IGFs to the tissues. A large proportion of the circulating IGFs are bound with high affinity to one of the binding proteins, IGFBP-3. The mechanism by which these IGFs are transferred from the circulatory pool to the tissue receptors is at present unclear. Recent studies in late pregnancy have demonstrated the presence of specific proteases which may modify the IGFBPs such that their affinities for the IGFs are reduced. In this paper, we have demonstrated the presence of a heat-sensitive cation-dependent proteolytic enzyme specific for IGFBP-3 in the serum of five severely ill patients. The activity of this protease was found to vary in these patients, becoming more apparent during fasting than when studied after commencement of parenteral nutrition, indicating that one of the influencing factors in the activity of this protease is the nutritional intake of the patient. Age- and sex-matched healthy adults were also studied in a similar protocol, but no proteolytic modification of any of the IGFBPs was found in any of the samples examined. As the levels of both IGF-I and IGF-II were found to be low in the patients, the presence of a circulatory protease suggests that this may be an adaptive response to increase the bioavailability of the IGFs and possibly to improve the nitrogen retention and counter the catabolic state in severe illness. Journal of Endocrinology (1991) 130,469–473


1984 ◽  
Vol 246 (1) ◽  
pp. C131-C140 ◽  
Author(s):  
E. M. Rosenberg ◽  
A. D. Goodman ◽  
T. L. Lipinski

In the present study we have demonstrated specific binding of 3H-labeled adenosine 3',5'-cyclic monophosphate (cAMP) to a nuclear extract from rat liver. GTP, GDP, and low concentrations of ATP and ADP increased nuclear binding of [3H]cAMP, and AMP inhibited [3H]cAMP binding. Photoaffinity labeling studies employing [32P]cAMP revealed four nuclear binding proteins [relative molecular weight (Mr) 36,000, 49,000, 54,000 and 57,000]. Unlabeled cAMP decreased [32P]cAMP binding to all four proteins, whereas GTP increased binding to the 57,000 protein. We also observed specific binding of [3H]cAMP in the liver cytosol, which was stimulated by GTP but not by ADP or ATP. Photoaffinity labeling studies of the cytosol in the absence of unlabeled nucleotides revealed three cAMP-binding proteins (Mr 36,000, 49,000, and 54,000). Unlabeled cAMP inhibited binding of [32P]cAMP to all three proteins, whereas in the presence of GTP there was binding of [32P]cAMP to a Mr 57,000 protein. Using DEAE-cellulose, we isolated from the nuclear extract and cytosol a cAMP-binding protein that responded to GTP with an increase in cAMP binding but was unaffected by GDP, ATP, ADP, and AMP. Guanosine imidodiphosphate did not affect cAMP binding, suggesting that the stimulatory effect of GTP may be mediated by phosphorylation. We speculate that alterations in intracellular GTP in vivo may modulate the binding of cAMP to a protein in the nucleus and cytosol.


2014 ◽  
Vol 289 (46) ◽  
pp. 31846-31855 ◽  
Author(s):  
Pauline Bonvin ◽  
Steven M. Dunn ◽  
François Rousseau ◽  
Douglas P. Dyer ◽  
Jeffrey Shaw ◽  
...  

2006 ◽  
Vol 352 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Kiyoshi Yamamoto ◽  
Akira Yamazaki ◽  
Mikio Takeuchi ◽  
Akito Tanaka

RNA Biology ◽  
2014 ◽  
Vol 11 (6) ◽  
pp. 669-672 ◽  
Author(s):  
Xiao Wang ◽  
Chuan He

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