Journal Article

FZJ-2021-05930

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The crystallization enthalpy and entropy of protein solutions: microcalorimetry, van't Hoff determination and linearized Poisson–Boltzmann model of tetragonal lysozyme crystals

Hentschel, L. ; Hansen, J.Extern* ; Egelhaaf, S. U. ; Platten, F. (Corresponding author)FZJ*

2021
RSC Publ. Cambridge

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Please use a persistent id in citations: http://hdl.handle.net/2128/30103  doi:10.1039/D0CP06113A

Abstract: During a first-order phase transition, a thermodynamic system releases or absorbs latent heat. Despite their fundamental importance, the heat or enthalpy change occurring during protein crystallization has been directly measured only in a few cases, and the associated entropy change can only be determined indirectly. This work provides an experimental determination and theoretical analysis of the dependence of the molar crystallization enthalpy of lysozyme solutions, ΔHxtal, on the physicochemical solution parameters. Its value is determined directly by isothermal microcalorimetry and indirectly by a van't Hoff analysis of solubility data, which quantitatively agree. This suggests a two-state crystallization process, in which oligomeric intermediates play a minor role. ΔHxtal is found to be negative on the order of few tens of the thermal energy per molecule. It is independent of protein concentration and stirring speed, but weakly depends on salt (NaCl) concentration and solution pH. Assuming that crystals are electrostatically neutral, these trends are explained by a linearized Poisson–Boltzmann theory. In addition, the molar crystallization entropy, ΔSxtal, is analyzed. The dependence of the van't Hoff entropy on salt concentration and pH is captured by the model, complementing the analysis of crystallization thermodynamics.

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Contributing Institute(s):

1. Biomakromolekulare Systeme und Prozesse (IBI-4)

Research Program(s):

1. 5241 - Molecular Information Processing in Cellular Systems (POF4-524) (POF4-524)

Appears in the scientific report 2021

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Database coverage:
; ; ; Allianz-Lizenz / DFG ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; National-Konsortium ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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