Conformational destabilization of Immunoglobulin G increases the low pH-binding affinity with the Neonatal Fc Receptor

Benjamin T Walters; Pernille Foged Jensen; Vincent Larraillet; Kevin Lin; Tom Patapoff; Tilman Schlothauer; Kasper Dyrberg Rand; Jennifer  Zhang

doi:10.1074/jbc.m115.691568

Conformational destabilization of Immunoglobulin G increases the low pH-binding affinity with the Neonatal Fc Receptor

Benjamin T Walters, Pernille Foged Jensen, Vincent Larraillet, Kevin Lin, Tom Patapoff, Tilman Schlothauer, Kasper Dyrberg Rand, Jennifer Zhang

22 Citations (Scopus)

Abstract

Crystallographic evidence suggests that the pH-dependent affinity of IgG molecules for the neonatal Fc receptor (FcRn) receptor primarily arises from salt bridges involving IgG histidine residues, resulting in moderate affinity at mildly acidic conditions. However, this view does not explain the diversity in affinity found in IgG variants, such as the YTE mutant (M252Y,S254T,T256E), which increases affinity to FcRn by up to 10×. Here we compare hydrogen exchange measurements at pH 7.0 and pH 5.5 with and without FcRn bound with surface plasmon resonance estimates of dissociation constants and FcRn affinity chromatography. The combination of experimental results demonstrates that differences between an IgG and its cognate YTE mutant vary with their pH-sensitive dynamics prior to binding FcRn. The conformational dynamics of these two molecules are nearly indistinguishable upon binding FcRn. We present evidence that pH-induced destabilization in the CH2/3 domain interface of IgG increases binding affinity by breaking intramolecular H-bonds and increases side-chain adaptability in sites that form intermolecular contacts with FcRn. Our results provide new insights into the mechanism of pH-dependent affinity in IgG-FcRn interactions and exemplify the important and often ignored role of intrinsic conformational dynamics in a protein ligand, to dictate affinity for biologically important receptors.

Original language	English
Journal	Journal of Biological Chemistry
Volume	291
Issue number	4
Pages (from-to)	1817-1825
Number of pages	9
ISSN	0021-9258
DOIs	https://doi.org/10.1074/jbc.m115.691568
Publication status	Published - 22 Jan 2016

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title = "Conformational destabilization of Immunoglobulin G increases the low pH-binding affinity with the Neonatal Fc Receptor",

abstract = "Crystallographic evidence suggests that the pH-dependent affinity of IgG molecules for the neonatal Fc receptor (FcRn) receptor primarily arises from salt bridges involving IgG histidine residues, resulting in moderate affinity at mildly acidic conditions. However, this view does not explain the diversity in affinity found in IgG variants, such as the YTE mutant (M252Y,S254T,T256E), which increases affinity to FcRn by up to 10×. Here we compare hydrogen exchange measurements at pH 7.0 and pH 5.5 with and without FcRn bound with surface plasmon resonance estimates of dissociation constants and FcRn affinity chromatography. The combination of experimental results demonstrates that differences between an IgG and its cognate YTE mutant vary with their pH-sensitive dynamics prior to binding FcRn. The conformational dynamics of these two molecules are nearly indistinguishable upon binding FcRn. We present evidence that pH-induced destabilization in the CH2/3 domain interface of IgG increases binding affinity by breaking intramolecular H-bonds and increases side-chain adaptability in sites that form intermolecular contacts with FcRn. Our results provide new insights into the mechanism of pH-dependent affinity in IgG-FcRn interactions and exemplify the important and often ignored role of intrinsic conformational dynamics in a protein ligand, to dictate affinity for biologically important receptors. ",

author = "Walters, {Benjamin T} and Jensen, {Pernille Foged} and Vincent Larraillet and Kevin Lin and Tom Patapoff and Tilman Schlothauer and Rand, {Kasper Dyrberg} and Jennifer Zhang",

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T1 - Conformational destabilization of Immunoglobulin G increases the low pH-binding affinity with the Neonatal Fc Receptor

AU - Walters, Benjamin T

AU - Jensen, Pernille Foged

AU - Larraillet, Vincent

AU - Lin, Kevin

AU - Patapoff, Tom

AU - Schlothauer, Tilman

AU - Rand, Kasper Dyrberg

AU - Zhang, Jennifer

PY - 2016/1/22

Y1 - 2016/1/22

N2 - Crystallographic evidence suggests that the pH-dependent affinity of IgG molecules for the neonatal Fc receptor (FcRn) receptor primarily arises from salt bridges involving IgG histidine residues, resulting in moderate affinity at mildly acidic conditions. However, this view does not explain the diversity in affinity found in IgG variants, such as the YTE mutant (M252Y,S254T,T256E), which increases affinity to FcRn by up to 10×. Here we compare hydrogen exchange measurements at pH 7.0 and pH 5.5 with and without FcRn bound with surface plasmon resonance estimates of dissociation constants and FcRn affinity chromatography. The combination of experimental results demonstrates that differences between an IgG and its cognate YTE mutant vary with their pH-sensitive dynamics prior to binding FcRn. The conformational dynamics of these two molecules are nearly indistinguishable upon binding FcRn. We present evidence that pH-induced destabilization in the CH2/3 domain interface of IgG increases binding affinity by breaking intramolecular H-bonds and increases side-chain adaptability in sites that form intermolecular contacts with FcRn. Our results provide new insights into the mechanism of pH-dependent affinity in IgG-FcRn interactions and exemplify the important and often ignored role of intrinsic conformational dynamics in a protein ligand, to dictate affinity for biologically important receptors.

AB - Crystallographic evidence suggests that the pH-dependent affinity of IgG molecules for the neonatal Fc receptor (FcRn) receptor primarily arises from salt bridges involving IgG histidine residues, resulting in moderate affinity at mildly acidic conditions. However, this view does not explain the diversity in affinity found in IgG variants, such as the YTE mutant (M252Y,S254T,T256E), which increases affinity to FcRn by up to 10×. Here we compare hydrogen exchange measurements at pH 7.0 and pH 5.5 with and without FcRn bound with surface plasmon resonance estimates of dissociation constants and FcRn affinity chromatography. The combination of experimental results demonstrates that differences between an IgG and its cognate YTE mutant vary with their pH-sensitive dynamics prior to binding FcRn. The conformational dynamics of these two molecules are nearly indistinguishable upon binding FcRn. We present evidence that pH-induced destabilization in the CH2/3 domain interface of IgG increases binding affinity by breaking intramolecular H-bonds and increases side-chain adaptability in sites that form intermolecular contacts with FcRn. Our results provide new insights into the mechanism of pH-dependent affinity in IgG-FcRn interactions and exemplify the important and often ignored role of intrinsic conformational dynamics in a protein ligand, to dictate affinity for biologically important receptors.

U2 - 10.1074/jbc.m115.691568

DO - 10.1074/jbc.m115.691568

M3 - Journal article

C2 - 26627822

SN - 0021-9258

VL - 291

SP - 1817

EP - 1825

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 4

ER -

Conformational destabilization of Immunoglobulin G increases the low pH-binding affinity with the Neonatal Fc Receptor

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