TY - JOUR
T1 - Structural role of extracellular domain 1 of α-platelet-derived growth factor (PDGF) receptor for PDGF-AA and PDGF-BB binding
AU - Mahadevan, D.
AU - Yu, J. C.
AU - Saldanha, J. W.
AU - Thanki, N.
AU - McPhie, P.
AU - Uren, A.
AU - Larochelle, W. J.
AU - Heidaran, M. A.
PY - 1995
Y1 - 1995
N2 - The purpose of this study was to bacterially express, purify, and refold combinations of the extracellular immunoglobulin (Ig)-like domains (2-3, 1- 3, and 1-5) of the human α-platelet-derived growth factor receptor (αPDGFR) to characterize molecular interactions with its ligand, platelet-derived growth factor (PDGF). The far UV circular dichroism spectroscopy of the α- PDGFR extracellular domains (ECDs) revealed a predominantly β-sheet protein, with a structure consistent with folded Ig-like domains. The addition of PDGF-BB to these ECD types changed the conformation of all three types with a decrease in mean residue ellipticity in the following rank order: 1-5 = 1-3 > 2-3. In striking contrast, addition of PDGF-AA to these ECD types markedly changed the conformation of ECD 2-3, by an increased mean residue ellipticity but no changes were observed for ECDs 1-3 and 1-5. PDGF-AA bound to the immobilized ECD types 2-3, 1-3, and 1-5 at concentrations of 20, 11, and 7.5 nM, respectively. In contrast, PDGF-BB bound the ECD types 2-3, 1-3, and 1-5 at concentrations of 3, 3, and 2.2 nM, respectively. Scatchard analysis of binding studies using labeled ECDs indicated that PDGF-BB bound ECD 1-3 and ECD 2-3 with K(D) values of 74 and 72 nM, respectively. While, PDGF-AA bound ECD 1-3 and ECD 2-3 with K(D) values of 33 and 87 nM, respectively. Therefore, our results indicated that the loss of ECD 1 impaired the binding affinity of αPDGFR ECD 1-3 toward PDGF-AA without having a similar effect on PDGF-BB binding. Together all of our data suggest that ECD 1 is differentially required for proper orientation of PDGF-AA but not PDGF-BB binding determinant within ECDs 2 and 3.
AB - The purpose of this study was to bacterially express, purify, and refold combinations of the extracellular immunoglobulin (Ig)-like domains (2-3, 1- 3, and 1-5) of the human α-platelet-derived growth factor receptor (αPDGFR) to characterize molecular interactions with its ligand, platelet-derived growth factor (PDGF). The far UV circular dichroism spectroscopy of the α- PDGFR extracellular domains (ECDs) revealed a predominantly β-sheet protein, with a structure consistent with folded Ig-like domains. The addition of PDGF-BB to these ECD types changed the conformation of all three types with a decrease in mean residue ellipticity in the following rank order: 1-5 = 1-3 > 2-3. In striking contrast, addition of PDGF-AA to these ECD types markedly changed the conformation of ECD 2-3, by an increased mean residue ellipticity but no changes were observed for ECDs 1-3 and 1-5. PDGF-AA bound to the immobilized ECD types 2-3, 1-3, and 1-5 at concentrations of 20, 11, and 7.5 nM, respectively. In contrast, PDGF-BB bound the ECD types 2-3, 1-3, and 1-5 at concentrations of 3, 3, and 2.2 nM, respectively. Scatchard analysis of binding studies using labeled ECDs indicated that PDGF-BB bound ECD 1-3 and ECD 2-3 with K(D) values of 74 and 72 nM, respectively. While, PDGF-AA bound ECD 1-3 and ECD 2-3 with K(D) values of 33 and 87 nM, respectively. Therefore, our results indicated that the loss of ECD 1 impaired the binding affinity of αPDGFR ECD 1-3 toward PDGF-AA without having a similar effect on PDGF-BB binding. Together all of our data suggest that ECD 1 is differentially required for proper orientation of PDGF-AA but not PDGF-BB binding determinant within ECDs 2 and 3.
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U2 - 10.1074/jbc.270.46.27595
DO - 10.1074/jbc.270.46.27595
M3 - Article
C2 - 7499222
AN - SCOPUS:0028790775
SN - 0021-9258
VL - 270
SP - 27595
EP - 27600
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 46
ER -