Charge reduction stabilizes intact membrane protein complexes for mass spectrometry

TY - JOUR

T1 - Charge reduction stabilizes intact membrane protein complexes for mass spectrometry

AU - Mehmood, Shahid

AU - Marcoux, Julien

AU - Hopper, Jonathan T S

AU - Allison, Timothy M.

AU - Liko, Idlir

AU - Borysik, Antoni J.

AU - Robinson, Carol V.

PY - 2014/12/10

Y1 - 2014/12/10

N2 - The study of intact soluble protein assemblies by means of mass spectrometry is providing invaluable contributions to structural biology and biochemistry. A recent breakthrough has enabled similar study of membrane protein complexes, following their release from detergent micelles in the gas phase. Careful optimization of mass spectrometry conditions, particularly with respect to energy regimes, is essential for maintaining compact folded states as detergent is removed. However, many of the saccharide detergents widely employed in structural biology can cause unfolding of membrane proteins in the gas phase. Here, we investigate the potential of charge reduction by introducing three membrane protein complexes from saccharide detergents and show how reducing their overall charge enables generation of compact states, as evidenced by ion mobility mass spectrometry. We find that charge reduction stabilizes the oligomeric state and enhances the stability of lipid-bound complexes. This finding is significant since maintaining native-like membrane proteins enables ligand binding to be assessed from a range of detergents that retain solubility while protecting the overall fold.

AB - The study of intact soluble protein assemblies by means of mass spectrometry is providing invaluable contributions to structural biology and biochemistry. A recent breakthrough has enabled similar study of membrane protein complexes, following their release from detergent micelles in the gas phase. Careful optimization of mass spectrometry conditions, particularly with respect to energy regimes, is essential for maintaining compact folded states as detergent is removed. However, many of the saccharide detergents widely employed in structural biology can cause unfolding of membrane proteins in the gas phase. Here, we investigate the potential of charge reduction by introducing three membrane protein complexes from saccharide detergents and show how reducing their overall charge enables generation of compact states, as evidenced by ion mobility mass spectrometry. We find that charge reduction stabilizes the oligomeric state and enhances the stability of lipid-bound complexes. This finding is significant since maintaining native-like membrane proteins enables ligand binding to be assessed from a range of detergents that retain solubility while protecting the overall fold.

UR - http://www.scopus.com/inward/record.url?scp=84918578801&partnerID=8YFLogxK

U2 - 10.1021/ja510283g

DO - 10.1021/ja510283g

M3 - Article

AN - SCOPUS:84918578801

SN - 0002-7863

VL - 136

SP - 17010

EP - 17012

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 49

ER -