Protein cold denaturation as seen from the solvent
(2009) In Journal of the American Chemical Society 131(3). p.1025-1036- Abstract
- Unlike most ordered molecular systems, globular proteins exhibit a temperature of maximum stability, implying that the structure can be disrupted by cooling. This cold denaturation phenomenon is usually linked to the temperature-dependent hydrophobic driving force for protein folding. Yet, despite the key role played by protein−water interactions, hydration changes during cold denaturation have not been investigated experimentally. Here, we use water−17O spin relaxation to monitor the hydration dynamics of the proteins BPTI, ubiquitin, apomyoglobin, and β-lactoglobulin in aqueous solution from room temperature down to −35 °C. To access this temperature range without ice formation, we contained the protein solution in nonperturbing... (More)
- Unlike most ordered molecular systems, globular proteins exhibit a temperature of maximum stability, implying that the structure can be disrupted by cooling. This cold denaturation phenomenon is usually linked to the temperature-dependent hydrophobic driving force for protein folding. Yet, despite the key role played by protein−water interactions, hydration changes during cold denaturation have not been investigated experimentally. Here, we use water−17O spin relaxation to monitor the hydration dynamics of the proteins BPTI, ubiquitin, apomyoglobin, and β-lactoglobulin in aqueous solution from room temperature down to −35 °C. To access this temperature range without ice formation, we contained the protein solution in nonperturbing picoliter emulsion droplets. Among the four proteins, only the destabilized apomyoglobin was observed to cold denature. Ubiquitin was found to be thermodynamically stable at least down to −32 °C, whereas β-lactoglobulin is expected to be unstable below −5 °C but remains kinetically trapped in the native state. When destabilized by 4 M urea, β-lactoglobulin cold denatures at 10 °C, as found previously by other methods. As seen from the solvent, the cold-denatured states of apomyoglobin in water and β-lactoglobulin in 4 M urea are relatively compact and are better described as solvent-penetrated than as unfolded. This finding challenges the popular analogy between cold denaturation and the anomalous low-temperature increase in aqueous solubility of nonpolar molecules. Our results also suggest that the reported cold denaturation at −20 °C of ubiquitin encapsulated in reverse micelles is caused by the low water content rather than by the low temperature. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1292741
- author
- Davidovic, Monika LU ; Mattea, Carlos LU ; Qvist, Johan LU and Halle, Bertil LU
- organization
- publishing date
- 2009
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of the American Chemical Society
- volume
- 131
- issue
- 3
- pages
- 1025 - 1036
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000264791600042
- scopus:61749085446
- ISSN
- 1520-5126
- DOI
- 10.1021/ja8056419
- language
- English
- LU publication?
- yes
- id
- 59bb1196-24eb-433d-9855-9f47e2375da3 (old id 1292741)
- date added to LUP
- 2016-04-01 12:51:11
- date last changed
- 2022-04-21 18:22:12
@article{59bb1196-24eb-433d-9855-9f47e2375da3,
abstract = {{Unlike most ordered molecular systems, globular proteins exhibit a temperature of maximum stability, implying that the structure can be disrupted by cooling. This cold denaturation phenomenon is usually linked to the temperature-dependent hydrophobic driving force for protein folding. Yet, despite the key role played by protein−water interactions, hydration changes during cold denaturation have not been investigated experimentally. Here, we use water−17O spin relaxation to monitor the hydration dynamics of the proteins BPTI, ubiquitin, apomyoglobin, and β-lactoglobulin in aqueous solution from room temperature down to −35 °C. To access this temperature range without ice formation, we contained the protein solution in nonperturbing picoliter emulsion droplets. Among the four proteins, only the destabilized apomyoglobin was observed to cold denature. Ubiquitin was found to be thermodynamically stable at least down to −32 °C, whereas β-lactoglobulin is expected to be unstable below −5 °C but remains kinetically trapped in the native state. When destabilized by 4 M urea, β-lactoglobulin cold denatures at 10 °C, as found previously by other methods. As seen from the solvent, the cold-denatured states of apomyoglobin in water and β-lactoglobulin in 4 M urea are relatively compact and are better described as solvent-penetrated than as unfolded. This finding challenges the popular analogy between cold denaturation and the anomalous low-temperature increase in aqueous solubility of nonpolar molecules. Our results also suggest that the reported cold denaturation at −20 °C of ubiquitin encapsulated in reverse micelles is caused by the low water content rather than by the low temperature.}},
author = {{Davidovic, Monika and Mattea, Carlos and Qvist, Johan and Halle, Bertil}},
issn = {{1520-5126}},
language = {{eng}},
number = {{3}},
pages = {{1025--1036}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Journal of the American Chemical Society}},
title = {{Protein cold denaturation as seen from the solvent}},
url = {{http://dx.doi.org/10.1021/ja8056419}},
doi = {{10.1021/ja8056419}},
volume = {{131}},
year = {{2009}},
}