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On the question of two-step nucleation in protein crystallization

Sauter, Andrea ; Roosen-Runge, Felix LU ; Zhang, Fajun ; Lotze, Gudrun LU ; Feoktystov, Artem ; Jacobs, Robert M.J. and Schreiber, Frank (2015) In Faraday Discussions 179. p.41-58
Abstract

We report a real-time study on protein crystallization in the presence of multivalent salts using small angle X-ray scattering (SAXS) and optical microscopy, focusing particularly on the nucleation mechanism as well as on the role of the metastable intermediate phase (MIP). Using bovine beta-lactoglobulin as a model system in the presence of the divalent salt CdCl2, we have monitored the early stage of crystallization kinetics which demonstrates a two-step nucleation mechanism: protein aggregates form a MIP, which is followed by the nucleation of crystals within the MIP. Here we focus on characterizing and tuning the structure of the MIP using salt and the related effects on the two-step nucleation kinetics. The results... (More)

We report a real-time study on protein crystallization in the presence of multivalent salts using small angle X-ray scattering (SAXS) and optical microscopy, focusing particularly on the nucleation mechanism as well as on the role of the metastable intermediate phase (MIP). Using bovine beta-lactoglobulin as a model system in the presence of the divalent salt CdCl2, we have monitored the early stage of crystallization kinetics which demonstrates a two-step nucleation mechanism: protein aggregates form a MIP, which is followed by the nucleation of crystals within the MIP. Here we focus on characterizing and tuning the structure of the MIP using salt and the related effects on the two-step nucleation kinetics. The results suggest that increasing the salt concentration near the transition zone pseudo-c∗∗ enhances the energy barrier for both MIPs and crystal nucleation, leading to slow growth. The structural evolution of the MIP and its effect on subsequent nucleation is discussed based on the growth kinetics. The observed kinetics can be well described, using a rate-equation model based on a clear physical two-step picture. This real-time study not only provides evidence for a two-step nucleation process for protein crystallization, but also elucidates the role and the structural signature of the MIPs in the nonclassical process of protein crystallization.

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author
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publishing date
type
Contribution to journal
publication status
published
in
Faraday Discussions
volume
179
pages
18 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:84937707389
  • pmid:25881044
ISSN
1359-6640
DOI
10.1039/c4fd00225c
language
English
LU publication?
no
id
cd6d9dfa-3e47-4b94-b6e4-a6ac5659382a
date added to LUP
2018-12-17 09:41:11
date last changed
2025-07-11 02:45:34
@article{cd6d9dfa-3e47-4b94-b6e4-a6ac5659382a,
  abstract     = {{<p>We report a real-time study on protein crystallization in the presence of multivalent salts using small angle X-ray scattering (SAXS) and optical microscopy, focusing particularly on the nucleation mechanism as well as on the role of the metastable intermediate phase (MIP). Using bovine beta-lactoglobulin as a model system in the presence of the divalent salt CdCl<sub>2</sub>, we have monitored the early stage of crystallization kinetics which demonstrates a two-step nucleation mechanism: protein aggregates form a MIP, which is followed by the nucleation of crystals within the MIP. Here we focus on characterizing and tuning the structure of the MIP using salt and the related effects on the two-step nucleation kinetics. The results suggest that increasing the salt concentration near the transition zone pseudo-c∗∗ enhances the energy barrier for both MIPs and crystal nucleation, leading to slow growth. The structural evolution of the MIP and its effect on subsequent nucleation is discussed based on the growth kinetics. The observed kinetics can be well described, using a rate-equation model based on a clear physical two-step picture. This real-time study not only provides evidence for a two-step nucleation process for protein crystallization, but also elucidates the role and the structural signature of the MIPs in the nonclassical process of protein crystallization.</p>}},
  author       = {{Sauter, Andrea and Roosen-Runge, Felix and Zhang, Fajun and Lotze, Gudrun and Feoktystov, Artem and Jacobs, Robert M.J. and Schreiber, Frank}},
  issn         = {{1359-6640}},
  language     = {{eng}},
  month        = {{01}},
  pages        = {{41--58}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Faraday Discussions}},
  title        = {{On the question of two-step nucleation in protein crystallization}},
  url          = {{http://dx.doi.org/10.1039/c4fd00225c}},
  doi          = {{10.1039/c4fd00225c}},
  volume       = {{179}},
  year         = {{2015}},
}