Advanced

Salting the charged surface: pH and salt dependence of protein G B1 stability

Lindman, Stina LU ; Xue, Wei-Feng LU ; Szczepankiewicz, Olga LU ; Bauer, Mikael LU ; Nilsson, Hanna LU and Linse, Sara LU (2006) In Biophysical Journal 90(8). p.2911-2921
Abstract
This study shows signicant effects of protein surface charges on stability and these effects are not eliminated by salt screening. The stability for a variant of protein G B1 domain was studied in the pH-range of 1.5-11 at low, 0.15 M, and 2 M salt. The variant has three mutations, T2Q, N8D, and N37D, to guarantee an intact covalent chain at all pH values. The stability of the protein shows distinct pH dependence with the highest stability close to the isoelectric point. The stability is pH-dependent at all three NaCl concentrations, indicating that interactions involving charged residues are important at all three conditions. We find that 2 M salt stabilizes the protein at low pH (protein net charge is +6 and total number of charges is 6)... (More)
This study shows signicant effects of protein surface charges on stability and these effects are not eliminated by salt screening. The stability for a variant of protein G B1 domain was studied in the pH-range of 1.5-11 at low, 0.15 M, and 2 M salt. The variant has three mutations, T2Q, N8D, and N37D, to guarantee an intact covalent chain at all pH values. The stability of the protein shows distinct pH dependence with the highest stability close to the isoelectric point. The stability is pH-dependent at all three NaCl concentrations, indicating that interactions involving charged residues are important at all three conditions. We find that 2 M salt stabilizes the protein at low pH (protein net charge is +6 and total number of charges is 6) but not at high pH (net charge is <=-6 and total number of charges is >= 18). Furthermore, 0.15 M salt slightly decreases the stability of the protein over the pH range. The results show that a net charge of the protein is destabilizing and indicate that proteins contain charges for reasons other than improved stability. Salt seems to reduce the electrostatic contributions to stability under conditions with few total charges, but cannot eliminate electrostatic effects in highly charged systems. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biophysical Journal
volume
90
issue
8
pages
2911 - 2921
publisher
Cell Press
external identifiers
  • wos:000236226900025
  • pmid:16443658
  • scopus:33646186493
ISSN
1542-0086
DOI
10.1529/biophysj.105.071050
language
English
LU publication?
yes
id
d9493c9a-90d3-40e2-b5f5-596c46770e89 (old id 415236)
date added to LUP
2007-10-08 16:08:54
date last changed
2019-07-14 03:33:02
@article{d9493c9a-90d3-40e2-b5f5-596c46770e89,
  abstract     = {This study shows signicant effects of protein surface charges on stability and these effects are not eliminated by salt screening. The stability for a variant of protein G B1 domain was studied in the pH-range of 1.5-11 at low, 0.15 M, and 2 M salt. The variant has three mutations, T2Q, N8D, and N37D, to guarantee an intact covalent chain at all pH values. The stability of the protein shows distinct pH dependence with the highest stability close to the isoelectric point. The stability is pH-dependent at all three NaCl concentrations, indicating that interactions involving charged residues are important at all three conditions. We find that 2 M salt stabilizes the protein at low pH (protein net charge is +6 and total number of charges is 6) but not at high pH (net charge is &lt;=-6 and total number of charges is &gt;= 18). Furthermore, 0.15 M salt slightly decreases the stability of the protein over the pH range. The results show that a net charge of the protein is destabilizing and indicate that proteins contain charges for reasons other than improved stability. Salt seems to reduce the electrostatic contributions to stability under conditions with few total charges, but cannot eliminate electrostatic effects in highly charged systems.},
  author       = {Lindman, Stina and Xue, Wei-Feng and Szczepankiewicz, Olga and Bauer, Mikael and Nilsson, Hanna and Linse, Sara},
  issn         = {1542-0086},
  language     = {eng},
  number       = {8},
  pages        = {2911--2921},
  publisher    = {Cell Press},
  series       = {Biophysical Journal},
  title        = {Salting the charged surface: pH and salt dependence of protein G B1 stability},
  url          = {http://dx.doi.org/10.1529/biophysj.105.071050},
  volume       = {90},
  year         = {2006},
}