1FPW

STRUCTURE OF YEAST FREQUENIN


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 40 
  • Conformers Submitted: 20 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum, structures with acceptable covalent geometry, structures with favorable non-bond energy, structures with the least restraint violations, structures with the lowest energy, target function 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure and calcium-binding properties of Frq1, a novel calcium sensor in the yeast Saccharomyces cerevisiae.

Ames, J.B.Hendricks, K.B.Strahl, T.Huttner, I.G.Hamasaki, N.Thorner, J.

(2000) Biochemistry 39: 12149-12161


  • PubMed Abstract: 
  • The FRQ1 gene is essential for growth of budding yeast and encodes a 190-residue, N-myristoylated (myr) calcium-binding protein. Frq1 belongs to the recoverin/frequenin branch of the EF-hand superfamily and regulates a yeast phosphatidylinositol 4-ki ...

    The FRQ1 gene is essential for growth of budding yeast and encodes a 190-residue, N-myristoylated (myr) calcium-binding protein. Frq1 belongs to the recoverin/frequenin branch of the EF-hand superfamily and regulates a yeast phosphatidylinositol 4-kinase isoform. Conformational changes in Frq1 due to N-myristoylation and Ca(2+) binding were assessed by nuclear magnetic resonance (NMR), fluorescence, and equilibrium Ca(2+)-binding measurements. For this purpose, Frq1 and myr-Frq1 were expressed in and purified from Escherichia coli. At saturation, Frq1 bound three Ca(2+) ions at independent sites, which correspond to the second, third, and fourth EF-hand motifs in the protein. Affinity of the second site (K(d) = 10 microM) was much weaker than that of the third and fourth sites (K(d) = 0.4 microM). Myr-Frq1 bound Ca(2+) with a K(d)app of 3 microM and a positive Hill coefficient (n = 1.25), suggesting that the N-myristoyl group confers some degree of cooperativity in Ca(2+) binding, as seen previously in recoverin. Both the NMR and fluorescence spectra of Frq1 exhibited very large Ca(2+)-dependent differences, indicating major conformational changes induced upon Ca(2+) binding. Nearly complete sequence-specific NMR assignments were obtained for the entire carboxy-terminal domain (residues K100-I190). Assignments were made for 20% of the residues in the amino-terminal domain; unassigned residues exhibited very broad NMR signals, most likely due to Frq1 dimerization. NMR chemical shifts and nuclear Overhauser effect (NOE) patterns of Ca(2+)-bound Frq1 were very similar to those of Ca(2+)-bound recoverin, suggesting that the overall structure of Frq1 resembles that of recoverin. A model of the three-dimensional structure of Ca(2+)-bound Frq1 is presented based on the NMR data and homology to recoverin. N-myristoylation of Frq1 had little or no effect on its NMR and fluorescence spectra, suggesting that the myristoyl moiety does not significantly alter Frq1 structure. Correspondingly, the NMR chemical shifts for the myristoyl group in both Ca(2+)-free and Ca(2+)-bound myr-Frq1 were nearly identical to those of free myristate in solution, indicating that the fatty acyl chain is solvent-exposed and not sequestered within the hydrophobic core of the protein, unlike the myristoyl group in Ca(2+)-free recoverin. Subcellular fractionation experiments showed that both the N-myristoyl group and Ca(2+)-binding contribute to the ability of Frq1 to associate with membranes.


    Organizational Affiliation

    Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, Maryland 20850, USA. james@carb.nist.gov




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CALCIUM-BINDING PROTEIN NCS-1
A
190Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Gene Names: FRQ1 (NCS1)
Find proteins for Q06389 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to UniProtKB:  Q06389
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 40 
  • Conformers Submitted: 20 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum, structures with acceptable covalent geometry, structures with favorable non-bond energy, structures with the least restraint violations, structures with the lowest energy, target function 
Software Package:
Software NamePurpose
X-PLORrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-10-18
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance