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GuHCl and NaCl-dependent hydrogen exchange in MerP reveals a well-defined core with an unusual exchange pattern

Brorsson, Ann-Christin ; Lundqvist, Martin LU ; Sethson, Ingmar and Jonsson, Bengt-Harald (2006) In Journal of Molecular Biology 357(5). p.1634-1646
Abstract
We have analysed hydrogen exchange at amide groups to characterise the energy landscape of the 72 amino acid residue protein MerP. From the guanidine hydrochloride (GuHCl) dependence of exchange in the pre-transitional region we have determined free energy values of exchange (ΔGHX) and corresponding m-values for individual amide protons. Detailed analysis of the exchange patterns indicates that for one set of amide protons there is a weak dependence on denaturant, indicating that the exchange is dominated by local fluctuations. For another set of amide protons a linear, but much stronger, denaturant dependence is observed. Notably, the plots of free energy of exchange versus [GuHCl] for 16 amide protons show pronounced... (More)
We have analysed hydrogen exchange at amide groups to characterise the energy landscape of the 72 amino acid residue protein MerP. From the guanidine hydrochloride (GuHCl) dependence of exchange in the pre-transitional region we have determined free energy values of exchange (ΔGHX) and corresponding m-values for individual amide protons. Detailed analysis of the exchange patterns indicates that for one set of amide protons there is a weak dependence on denaturant, indicating that the exchange is dominated by local fluctuations. For another set of amide protons a linear, but much stronger, denaturant dependence is observed. Notably, the plots of free energy of exchange versus [GuHCl] for 16 amide protons show pronounced upward curvature, and a close inspection of the structure shows that these residues form a well-defined core in the protein. The hydrogen exchange that was measured at various concentrations of NaCl shows an apparent selective stabilisation of this core. Detailed analysis of this exchange pattern indicates that it may originate from selective destabilisation of the unfolded state by guanidinium ions and/or selective stabilisation of the core in the native state by chloride ions. (Less)
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publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Molecular Biology
volume
357
issue
5
pages
13 pages
publisher
Elsevier
external identifiers
  • scopus:33645087908
ISSN
1089-8638
DOI
10.1016/j.jmb.2006.01.090
language
English
LU publication?
no
id
fece32c3-c96f-4d36-9f8e-9f9d184f6276
date added to LUP
2021-10-19 12:10:42
date last changed
2022-02-02 00:39:27
@article{fece32c3-c96f-4d36-9f8e-9f9d184f6276,
  abstract     = {{We have analysed hydrogen exchange at amide groups to characterise the energy landscape of the 72 amino acid residue protein MerP. From the guanidine hydrochloride (GuHCl) dependence of exchange in the pre-transitional region we have determined free energy values of exchange (ΔG<sub>HX</sub>) and corresponding m-values for individual amide protons. Detailed analysis of the exchange patterns indicates that for one set of amide protons there is a weak dependence on denaturant, indicating that the exchange is dominated by local fluctuations. For another set of amide protons a linear, but much stronger, denaturant dependence is observed. Notably, the plots of free energy of exchange <i>versus </i>[GuHCl] for 16 amide protons show pronounced upward curvature, and a close inspection of the structure shows that these residues form a well-defined core in the protein. The hydrogen exchange that was measured at various concentrations of NaCl shows an apparent selective stabilisation of this core. Detailed analysis of this exchange pattern indicates that it may originate from selective destabilisation of the unfolded state by guanidinium ions and/or selective stabilisation of the core in the native state by chloride ions.}},
  author       = {{Brorsson, Ann-Christin and Lundqvist, Martin and Sethson, Ingmar and Jonsson, Bengt-Harald}},
  issn         = {{1089-8638}},
  language     = {{eng}},
  number       = {{5}},
  pages        = {{1634--1646}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Molecular Biology}},
  title        = {{GuHCl and NaCl-dependent hydrogen exchange in MerP reveals a well-defined core with an unusual exchange pattern}},
  url          = {{http://dx.doi.org/10.1016/j.jmb.2006.01.090}},
  doi          = {{10.1016/j.jmb.2006.01.090}},
  volume       = {{357}},
  year         = {{2006}},
}