Recoverin alters its surface properties depending on both calcium-binding and N-terminal myristoylation.
The solution structure and calcium-dependent structural changes of recoverin, a 23 kDa calcium binding protein of vertebrate photoreceptors, have been studied by small-angle X-ray scattering and CD, as well as the effect of N-terminal myristoylation. The CD spectrum is not affected by N-terminal myristoylation, but strongly affected by Ca2+, indicating that N-terminal myristoylation alone does not cause a conformational change. The major conformational change in recoverin induced by Ca2+ is characterized as a decrease in the alpha-helical content of the protein and an increase in global size upon removal of Ca2+. In the presence of Ca2+, unmyristoylated recoverin is monomeric and globular in solution, while N-terminal myristoylation brings about aggregation. In the absence of Ca2+, unmyristoylated recoverin tends to aggregate, while myristoylated recoverin becomes monomeric and globular. These observations indicate that recoverin changes its surface properties depending on both calcium binding and N-terminal myristoylation. Melittin interacts non-specifically only with the myristoylated recoverin in the absence of Ca2+. This may be indicative of the properties of the interaction between recoverin and its normal physiological target enzyme.
Kataoka
M
M
Department of Biology, Faculty of Science, Osaka University.
Mihara
K
K
Tokunaga
F
F
D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D002942:Circular Dichroism; D004533:Egtazic Acid / Q000494:pharmacology; D005136:Eye Proteins; D051597:Hippocalcin; D008074:Lipoproteins; D046911:Macromolecular Substances; D008555:Melitten / Q000494:pharmacology; D009227:Myristic Acids / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D017433:Protein Structure, Secondary / Q000187:drug effects; D011994:Recombinant Proteins; D051603:Recoverin; D012542:Scattering, Radiation; D012996:Solutions; D013050:Spectrometry, Fluorescence; D014965:X-Rays
D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D008074:Lipoproteins; D046911:Macromolecular Substances; D009227:Myristic Acids; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D012996:Solutions; D051603:Recoverin; D051597:Hippocalcin; D008555:Melitten; D004533:Egtazic Acid; D002118:Calcium