Effects of cyclic GMP on the secondary structure of cyclic GMP dependent protein kinase and analysis of the enzyme's amino-terminal domain by far-ultraviolet circular dichroism.
Far-UV circular dichroism spectra of bovine lung cyclic GMP dependent protein kinase (G-kinase) show that the enzyme contains alpha-helical and beta-pleated sheet elements. Binding of cyclic GMP changes the spectra in a way consistent with the induction of beta-sheet from random coil. Examination of the amino-terminal sequence of G-kinase indicates the presence of a strongly alpha-helical segment with several features in common with the leucine zipper motif. We propose that this sequence may be the important part of the dimerization domain of the enzyme. A synthetic peptide corresponding to amino acids 1-39 of G-kinase has a strongly alpha-helical CD spectrum, supporting the predicted secondary structure of this amino-terminal sequence. In contrast to the native enzyme, a structure reduced in alpha-helix was found when a constitutively active form of G-kinase, which lacks amino acids 1-77, was studied.
Landgraf
W
W
Institut für Medizinische Biochemie, Universität des Saarlandes, Homburg/Saar, FRG.
Hofmann
F
F
Pelton
J T
JT
Huggins
J P
JP
D000495:Allosteric Site; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002942:Circular Dichroism; D006152:Cyclic GMP / Q000378:metabolism / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry; D011487:Protein Conformation / Q000187:drug effects; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism*
D010446:Peptide Fragments; D011494:Protein Kinases; D006152:Cyclic GMP