TY - JOUR

T1 - Approximate calculation and experimental derivation of native isoelectric points of membrane protein complexes of Arabidopsis chloroplasts and mitochondria

AU - Behrens, Christof

AU - Hartmann, Kristina

AU - Sunderhaus, Stephanie

AU - Braun, Hans Peter

AU - Eubel, Holger

N1 - Funding information: We thank Dr. Nir Keren, Hebrew University of Jerusalem for cooperation, Michael Senkler for expert help in setting up nativepI and Marianne Langer for expert technical assistance. This joint research project was financially supported by the State of Lower-Saxony and the VolkswagenFoundation , Hannover, Germany (Project VWZN2326 ).

PY - 2012/11/29

Y1 - 2012/11/29

N2 - Electric charges are important intrinsic properties of proteins. They directly affect functionality and also mediate interactions with other molecules such as cofactors, substrates and regulators of enzymatic activity, with lipids as well as other proteins. As such, analysis of the electric properties of proteins gives rise to improved understanding of the mechanism by which proteins fulfil their specific functions. This is not only true for singular proteins but also applies for defined assemblies of proteins, protein complexes and supercomplexes. Charges in proteins often are a consequence of the presence of basic and acidic amino acid residues within polypeptide chains. In liquid phase, charge distributions of proteins change in response to the pH of their environment. The interdependence of protein charge and the surrounding pH is best described by the isoelectric point, which is notoriously difficult to obtain for native protein complexes. Here, experimentally derived native isoelectric points (npIs) for a range mitochondrial and plastid protein complexes are provided. In addition, for four complexes, npIs were calculated by a novel approach which yields results largely matching the experimental npIs.

AB - Electric charges are important intrinsic properties of proteins. They directly affect functionality and also mediate interactions with other molecules such as cofactors, substrates and regulators of enzymatic activity, with lipids as well as other proteins. As such, analysis of the electric properties of proteins gives rise to improved understanding of the mechanism by which proteins fulfil their specific functions. This is not only true for singular proteins but also applies for defined assemblies of proteins, protein complexes and supercomplexes. Charges in proteins often are a consequence of the presence of basic and acidic amino acid residues within polypeptide chains. In liquid phase, charge distributions of proteins change in response to the pH of their environment. The interdependence of protein charge and the surrounding pH is best described by the isoelectric point, which is notoriously difficult to obtain for native protein complexes. Here, experimentally derived native isoelectric points (npIs) for a range mitochondrial and plastid protein complexes are provided. In addition, for four complexes, npIs were calculated by a novel approach which yields results largely matching the experimental npIs.

KW - Chloroplasts

KW - Free flow electrophoresis

KW - Ionisable amino acids

KW - Membrane protein complexes

KW - Mitochondria

KW - Native isoelectric point

UR - http://www.scopus.com/inward/record.url?scp=84872120134&partnerID=8YFLogxK

U2 - 10.1016/j.bbamem.2012.11.028

DO - 10.1016/j.bbamem.2012.11.028

M3 - Article

C2 - 23201540

AN - SCOPUS:84872120134

VL - 1828

SP - 1036

EP - 1046

JO - Biochimica et Biophysica Acta - Biomembranes

JF - Biochimica et Biophysica Acta - Biomembranes

SN - 0005-2736

IS - 3

ER -