Topologic investigation of the NCKX2 Na+/Ca2+-K+ exchanger alpha-repeats.
Algorithms suggest that NCKX proteins consist of an N-terminal signal peptide and 11 transmembrane segments divided in two groups of 5 and 6, respectively, separated by a large cytoplasmic loop. This predicted topology places the NCKX alpha-repeats with the same orientation in the plasma membrane. Using thiol-specific drug treatment and site-directed disulfide mapping, we have investigated the orientation of the NCKX2 alpha-repeats. Our results suggest that the NCKX2 alpha-repeats have an antiparallel orientation in the plasma membrane. In addition, these experiments suggest that the alpha-repeats are found in close proximity in the mature configuration of the protein.
Kinjo
Tashi G
TG
Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, N.W. Calgary, Alberta, T2N 4N1, Canada.
Szerencsei
Robert T
RT
Schnetkamp
Paul P M
PP
D000465:Algorithms; D004220:Disulfides / Q000737:chemistry; D011487:Protein Conformation; D019831:Sodium-Calcium Exchanger / Q000737:chemistry*
D004220:Disulfides; D019831:Sodium-Calcium Exchanger; C074530:potassium-dependent sodium-calcium exchanger