Anharmonic behavior in the multisubunit protein apoferritin as revealed by quasi-elastic neutron scattering

M. T F Telling; Cameron Neylon; Susan H. Kilcoyne; Valeria Arrighi

doi:10.1021/jp801779x

Anharmonic behavior in the multisubunit protein apoferritin as revealed by quasi-elastic neutron scattering

M. T F Telling, Cameron Neylon, Susan H. Kilcoyne, Valeria Arrighi

School of Engineering & Physical Sciences

Research output: Contribution to journal › Article › peer-review

9 Citations (Scopus)

Abstract

Quasi-elastic neutron scattering (QENS) has been used to study the deviation from Debye-law harmonic behavior in lyophilized and hydrated apoferritin, a naturally occurring, multisubunit protein. Whereas analysis of the measured mean squared displacement (msd) parameter reveals a hydration-dependent inflection above 240 K, characteristic of diffusive motion, a hydration-independent inflection is observed at 100 K. The mechanism responsible for this low-temperature anharmonic response is further investigated, via analysis of the elastic incoherent neutron scattering intensity, by applying models developed to describe side-group motion in glassy polymers. Our results suggest that the deviation from harmonic behavior is due to the onset of methyl group rotations which exhibit a broad distribution of activated processes (E_a,ave = 12.2 kJ· mol^-1, s = 5.0 kJ·mol^-1). Our results are likened to those reported for other proteins. © 2008 American Chemical Society.

Original language	English
Pages (from-to)	10873-10878
Number of pages	6
Journal	Journal of Physical Chemistry B
Volume	112
Issue number	35
DOIs	https://doi.org/10.1021/jp801779x
Publication status	Published - 4 Sept 2008

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title = "Anharmonic behavior in the multisubunit protein apoferritin as revealed by quasi-elastic neutron scattering",

abstract = "Quasi-elastic neutron scattering (QENS) has been used to study the deviation from Debye-law harmonic behavior in lyophilized and hydrated apoferritin, a naturally occurring, multisubunit protein. Whereas analysis of the measured mean squared displacement (msd) parameter reveals a hydration-dependent inflection above 240 K, characteristic of diffusive motion, a hydration-independent inflection is observed at 100 K. The mechanism responsible for this low-temperature anharmonic response is further investigated, via analysis of the elastic incoherent neutron scattering intensity, by applying models developed to describe side-group motion in glassy polymers. Our results suggest that the deviation from harmonic behavior is due to the onset of methyl group rotations which exhibit a broad distribution of activated processes (Ea,ave = 12.2 kJ· mol-1, s = 5.0 kJ·mol-1). Our results are likened to those reported for other proteins. {\textcopyright} 2008 American Chemical Society.",

author = "Telling, {M. T F} and Cameron Neylon and Kilcoyne, {Susan H.} and Valeria Arrighi",

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doi = "10.1021/jp801779x",

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T1 - Anharmonic behavior in the multisubunit protein apoferritin as revealed by quasi-elastic neutron scattering

AU - Telling, M. T F

AU - Neylon, Cameron

AU - Kilcoyne, Susan H.

AU - Arrighi, Valeria

PY - 2008/9/4

Y1 - 2008/9/4

N2 - Quasi-elastic neutron scattering (QENS) has been used to study the deviation from Debye-law harmonic behavior in lyophilized and hydrated apoferritin, a naturally occurring, multisubunit protein. Whereas analysis of the measured mean squared displacement (msd) parameter reveals a hydration-dependent inflection above 240 K, characteristic of diffusive motion, a hydration-independent inflection is observed at 100 K. The mechanism responsible for this low-temperature anharmonic response is further investigated, via analysis of the elastic incoherent neutron scattering intensity, by applying models developed to describe side-group motion in glassy polymers. Our results suggest that the deviation from harmonic behavior is due to the onset of methyl group rotations which exhibit a broad distribution of activated processes (Ea,ave = 12.2 kJ· mol-1, s = 5.0 kJ·mol-1). Our results are likened to those reported for other proteins. © 2008 American Chemical Society.

AB - Quasi-elastic neutron scattering (QENS) has been used to study the deviation from Debye-law harmonic behavior in lyophilized and hydrated apoferritin, a naturally occurring, multisubunit protein. Whereas analysis of the measured mean squared displacement (msd) parameter reveals a hydration-dependent inflection above 240 K, characteristic of diffusive motion, a hydration-independent inflection is observed at 100 K. The mechanism responsible for this low-temperature anharmonic response is further investigated, via analysis of the elastic incoherent neutron scattering intensity, by applying models developed to describe side-group motion in glassy polymers. Our results suggest that the deviation from harmonic behavior is due to the onset of methyl group rotations which exhibit a broad distribution of activated processes (Ea,ave = 12.2 kJ· mol-1, s = 5.0 kJ·mol-1). Our results are likened to those reported for other proteins. © 2008 American Chemical Society.

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EP - 10878

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

IS - 35

ER -

Anharmonic behavior in the multisubunit protein apoferritin as revealed by quasi-elastic neutron scattering

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