Affinity purification of the photoreceptor cGMP-gated cation channel

J Biol Chem. 1991 May 5;266(13):7975-7.


The cGMP-gated cation channel is a member of a new family of channel proteins that appear to be directly regulated by cyclic nucleotides. A protein with a subunit molecular mass of 78 kDa that exhibits cGMP-gated calcium flux when reconstituted into phospholipid-containing vesicles has been purified using 8-bromo-cGMP-agarose affinity chromatography. This channel activity is sensitive to the inhibitor l-cis-diltiazem. Treatment of the reconstituted channel with trypsin abolishes the l-cis-diltiazem sensitivity. Apparent endogenous proteolysis can also result in smaller molecular weight polypeptides that exhibit cGMP-gated channel activity but are insensitive to l-cis-diltiazem. These results show that the channel can bind cGMP and that it contains a l-cis-diltiazem inhibitory domain that is distinct from the cGMP-binding domain.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blotting, Western
  • Cattle
  • Chromatography, Affinity
  • Cyclic GMP / analogs & derivatives
  • Cyclic Nucleotide-Gated Cation Channels
  • Diltiazem / pharmacology
  • Electrophoresis, Polyacrylamide Gel
  • Eye Proteins / isolation & purification*
  • Ion Channels*
  • Photoreceptor Cells / chemistry*
  • Trypsin / metabolism


  • Cyclic Nucleotide-Gated Cation Channels
  • Eye Proteins
  • Ion Channels
  • 8-bromocyclic GMP
  • Trypsin
  • Diltiazem
  • Cyclic GMP