TY - JOUR
T1 - Major intrinsic polypeptide of lens membrane. Biochemical and immunological characterization of the major cyanogen bromide fragment
AU - Takemoto, Larry J.
AU - Hansen, Jeff S.
AU - Nicholson, Bruce J.
AU - Hunkapiller, Michael
AU - Revel, Jean Paul
AU - Horwitz, Joseph
N1 - Funding Information:
This research was supported by grants from the National Institutes of Health to L.J.T. (EY 02932-04), J.-P.R. (GM 06965), and J.H.B.J.N. was supported by a fellowship from the Ross Foundation.
PY - 1983/6/10
Y1 - 1983/6/10
N2 - A protein of Mr 26 000 has been shown to be the major component of eye-lens junctions, which are similar but not identical to the gap junctions of liver and other tissues. Cyanogen bromide cleavage of the Mr 26 000 polypeptide from bovine lenses yields a major fragment of Mr 15 000 (fragment 1). However, if the junctions are first treated with trypsin or carboxypeptidase Y, cyanogen bromide treatment yields a fragment of reduced molecular weight. Since protease treatment has been shown to cleave residues almost exclusively from the carboxy-terminal end of the Mr 26 000 polypeptide, it follows that fragment 1 represents the carboxy-terminal half of this molecule, part of which is exposed to proteolytic attack outside the membrane. This latter result is corroborated by the fact that antisera which recognize both the Mr 26 000 polypeptide and fragment 1 fail to do so after preadsorption with intact membranes. In addition, comparative amino acid and partial sequence analyses of the Mr 26 000 polypeptide and fragment 1 indicate that fragment 1 is more hydrophilic in character, suggesting that much of the amino-terminal half of the Mr 26 000 polypeptide is buried within the lipid bilayer.
AB - A protein of Mr 26 000 has been shown to be the major component of eye-lens junctions, which are similar but not identical to the gap junctions of liver and other tissues. Cyanogen bromide cleavage of the Mr 26 000 polypeptide from bovine lenses yields a major fragment of Mr 15 000 (fragment 1). However, if the junctions are first treated with trypsin or carboxypeptidase Y, cyanogen bromide treatment yields a fragment of reduced molecular weight. Since protease treatment has been shown to cleave residues almost exclusively from the carboxy-terminal end of the Mr 26 000 polypeptide, it follows that fragment 1 represents the carboxy-terminal half of this molecule, part of which is exposed to proteolytic attack outside the membrane. This latter result is corroborated by the fact that antisera which recognize both the Mr 26 000 polypeptide and fragment 1 fail to do so after preadsorption with intact membranes. In addition, comparative amino acid and partial sequence analyses of the Mr 26 000 polypeptide and fragment 1 indicate that fragment 1 is more hydrophilic in character, suggesting that much of the amino-terminal half of the Mr 26 000 polypeptide is buried within the lipid bilayer.
KW - (Bovine and rat eye)
KW - Cyanogen bromide cleavage
KW - Lens junction
KW - Major intrinsic polypeptide
KW - immunological characterization
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U2 - 10.1016/0005-2736(83)90018-4
DO - 10.1016/0005-2736(83)90018-4
M3 - Article
C2 - 6849923
AN - SCOPUS:0021099590
SN - 0005-2736
VL - 731
SP - 267
EP - 274
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
IS - 2
ER -