2NA0

NMR structure of Guanylyl Cyclase Activator Protein 1 (GCAP1) mutant V77E in a Ca2+-free/Mg2+-bound Activator State

Summary for 2NA0

• Entry DOI: 10.2210/pdb2na0/pdb
• NMR Information: BMRB: 26688
• Descriptor: Guanylyl cyclase-activating protein 1 (1 entity in total)
• Functional Keywords: signal transduction, activator state, lyase activator
• Biological source: Bos taurus (bovine,cow,domestic cattle,domestic cow)
• Cellular location: Membrane; Lipid-anchor: P46065
• Total number of polymer chains: 1
• Total formula weight: 23641.46

Authors

Lim, S.,Ames, J.B. (deposition date: 2015-12-16, release date: 2015-12-30, Last modification date: 2023-06-14)

Primary citation

Lim, S.,Peshenko, I.V.,Olshevskaya, E.V.,Dizhoor, A.M.,Ames, J.B.
Structure of Guanylyl Cyclase Activator Protein 1 (GCAP1) Mutant V77E in a Ca2+-free/Mg2+-bound Activator State.
J.Biol.Chem., 291:4429-4441, 2016

PubMed Abstract: GCAP1, a member of the neuronal calcium sensor subclass of the calmodulin superfamily, confers Ca(2+)-sensitive activation of retinal guanylyl cyclase 1 (RetGC1). We present NMR resonance assignments, residual dipolar coupling data, functional analysis, and a structural model of GCAP1 mutant (GCAP1(V77E)) in the Ca(2+)-free/Mg(2+)-bound state. NMR chemical shifts and residual dipolar coupling data reveal Ca(2+)-dependent differences for residues 170-174. An NMR-derived model of GCAP1(V77E) contains Mg(2+) bound at EF2 and looks similar to Ca(2+) saturated GCAP1 (root mean square deviations = 2.0 Å). Ca(2+)-dependent structural differences occur in the fourth EF-hand (EF4) and adjacent helical region (residues 164-174 called the Ca(2+) switch helix). Ca(2+)-induced shortening of the Ca(2+) switch helix changes solvent accessibility of Thr-171 and Leu-174 that affects the domain interface. Although the Ca(2+) switch helix is not part of the RetGC1 binding site, insertion of an extra Gly residue between Ser-173 and Leu-174 as well as deletion of Arg-172, Ser-173, or Leu-174 all caused a decrease in Ca(2+) binding affinity and abolished RetGC1 activation. We conclude that Ca(2+)-dependent conformational changes in the Ca(2+) switch helix are important for activating RetGC1 and provide further support for a Ca(2+)-myristoyl tug mechanism.

PubMed: 26703466
DOI: 10.1074/jbc.M115.696161

Experimental method

SOLUTION NMR