G. Corcao et al., LATERAL DIFFUSION OF HUMAN CD2 WILD-TYPE AND MUTANTS WITH LARGE DELETIONS IN THE TRANSMEMBRANE DOMAIN, Biochemical and biophysical research communications, 208(3), 1995, pp. 1131-1136
Integral membrane proteins anchor to the cell surface and span the lip
id bilayer by an alpha-helix of 17-30 amino acids, the transmembrane s
egment. However, little is known about the association of this alpha-h
elix and the lipid bilayer. In the present study human CD2 molecule wa
s choosen as a model for an integral membrane protein. Truncate forms
with transmembrane segments 14 and 12 amino acids long were created by
oligonucleotide site-directed mutagenesis. Lateral diffusion revealed
that even large deletions in the membrane domain of CD2 do not interf
ere with its lateral mobility. On the other hand, the fraction of free
molecules for diffusion was higher in CD2 protein with transmembrane
region 12 amino acids long. These results suggest that deletions in th
e transmembrane domain can interfere with the stability of the protein
within the lipid bilayer. (C) 1995 Academic Press, Inc.