title: Ca2+ differently affects hydrophobic properties of guanylyl cyclase-activating proteins (GCAPs) and recoverin.
abstract: Guanylyl cyclase-activating proteins (GCAPs) and recoverin are retina-specific Ca(2+)-binding proteins involved in phototransduction. We provide here evidence that in spite of structural similarities GCAPs and recoverin differently change their overall hydrophobic properties in response to Ca(2+). Using native bovine GCAP1, GCAP2 and recoverin we show that: i) the Ca(2+)-dependent binding of recoverin to Phenyl-Sepharose is distinct from such interactions of GCAPs; ii) fluorescence intensity of 1-anilinonaphthalene-8-sulfonate (ANS) is markedly higher at high [Ca(2+)](free) (10 microM) than at low [Ca(2+)](free) (10 nM) in the presence of recoverin, while an opposing effect is observed in the presence of GCAPs; iii) fluorescence resonance energy transfer from tryptophane residues to ANS is more efficient at high [Ca(2+)](free) in recoverin and at low [Ca(2+)](free) in GCAP2. Such different changes of hydrophobicity evoked by Ca(2+) appear to be the precondition for possible mechanisms by which GCAPs and recoverin control the activities of their target enzymes.
authors.affiliation: Laboratory of Signaling Proteins, L. Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, 53-114 Wrocław, Poland. gorczyca@immuno.iitd.pan.wroc.pl
authors.forename: Wojciech A
authors.initials: WA
authors.lastname: Gorczyca
authors.forename: Marcin
authors.initials: M
authors.lastname: Kobiałka
authors.forename: Marianna
authors.initials: M
authors.lastname: Kuropatwa
authors.forename: Ewa
authors.initials: E
authors.lastname: Kurowska
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000737:chemistry* / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D002417:Cattle; D005136:Eye Proteins; D031541:Fluorescence Resonance Energy Transfer; D051604:Guanylate Cyclase-Activating Proteins; D051597:Hippocalcin; D057927:Hydrophobic and Hydrophilic Interactions; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; D011485:Protein Binding; D011487:Protein Conformation; D020033:Protein Isoforms; D051603:Recoverin; D012160:Retina / Q000737:chemistry; D012685:Sepharose / Q000031:analogs & derivatives* / Q000378:metabolism; D013050:Spectrometry, Fluorescence / Q000379:methods; D014364:Tryptophan / Q000737:chemistry / Q000378:metabolism
chemical_list: D000817:Anilino Naphthalenesulfonates; D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D051604:Guanylate Cyclase-Activating Proteins; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D051603:Recoverin; D051597:Hippocalcin; C027132:1-anilino-8-naphthalenesulfonate; C020927:phenyl-sepharose; D014364:Tryptophan; D012685:Sepharose; D002118:Calcium