Table 1.

Description of α mutants and summary results

Indicated is the figure in which the mutants appear with the indicated name, which specifies the number of membrane segments contained in the mutant and the point mutations introduced. All mutants start at Met-1. The description indicates the last amino acid of the α mutants or the composition of chimeric constructs. fl, full length α proteins, which contain the indicated point mutations. In the degradation column, the results on the degradation of α variants synthesized in the oocyte in the absence or presence of β subunits are summarized. +, α-proteins degraded after a 48-h chase; −, α-proteins not degraded after a 48-h chase; M, membrane segment; nd, not determined. At the bottom, a putative, linear model of the α subunit of Xenopus Na,K-ATPase is shown, which indicates the amino acids that define the putative transmembrane segments according to a 10-transmembrane segment model (Moller et al., 1996).