2MG5

Solution Structure of Calmodulin bound to the target peptide of Endothelial Nitrogen Oxide Synthase phosphorylated at Thr495


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 20 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with acceptable covalent geometry 

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This is version 1.1 of the entry. See complete history


Literature

Solution structure of calmodulin bound to the target Peptide of endothelial nitric oxide synthase phosphorylated at thr495.

Piazza, M.Taiakina, V.Guillemette, S.R.Guillemette, J.G.Dieckmann, T.

(2014) Biochemistry 53: 1241-1249

  • DOI: 10.1021/bi401466s
  • Primary Citation of Related Structures:  
    2MG5

  • PubMed Abstract: 
  • Nitric oxide synthase (NOS) plays a major role in a number of key physiological and pathological processes, and it is important to understand how this enzyme is regulated. The small acidic calcium binding protein, calmodulin (CaM), is required to fully activate the enzyme ...

    Nitric oxide synthase (NOS) plays a major role in a number of key physiological and pathological processes, and it is important to understand how this enzyme is regulated. The small acidic calcium binding protein, calmodulin (CaM), is required to fully activate the enzyme. The exact mechanism of how CaM activates NOS is not fully understood at this time. Studies have shown CaM to act like a switch that causes a conformational change in NOS to allow for the transfer of an electron between the reductase and oxygenase domains through a process that is thought to be highly dynamic and at least in part controlled by several possible phosphorylation sites. We have determined the solution structure of CaM bound to a peptide that contains a phosphorylated threonine corresponding to Thr495 in full size endothelial NOS (eNOS) to investigate the structural and functional effects that the phosphorylation of this residue may have on nitric oxide production. Our biophysical studies show that phosphorylation of Thr495 introduces electrostatic repulsions between the target sequence and CaM as well as a diminished propensity for the peptide to form an α-helix. The calcium affinity of the CaM-target peptide complex is reduced because of phosphorylation, and this leads to weaker binding at low physiological calcium concentrations. This study provides an explanation for the reduced level of NO production by eNOS carrying a phosphorylated Thr495 residue.


    Organizational Affiliation

    Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CalmodulinA148Homo sapiensMutation(s): 0 
Gene Names: 
CALM1CALMCAMCAM1CALM2CAM2CAMBCALM3CALML2CAM3...
CALM1CALMCAMCAM1CALM2CAM2CAMBCALM3CALML2CAM3CAMCCAMIII

UniProt & NIH Common Fund Data Resources
Find proteins for P0DP23 (Homo sapiens)
Explore P0DP23 
Go to UniProtKB:  P0DP23
PHAROS:  P0DP23
Entity Groups  
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UniProt GroupP0DP23
Protein Feature View
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  • Reference Sequence

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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
target peptideB16N/AMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P29474 (Homo sapiens)
Explore P29474 
Go to UniProtKB:  P29474
PHAROS:  P29474
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP29474
Protein Feature View
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  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
TPO
Query on TPO
B L-PEPTIDE LINKINGC4 H10 N O6 PTHR
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 20 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with acceptable covalent geometry 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-03-05
    Type: Initial release
  • Version 1.1: 2014-03-19
    Changes: Database references