1IAQ

C-H-RAS P21 PROTEIN MUTANT WITH THR 35 REPLACED BY SER (T35S) COMPLEXED WITH GUANOSINE-5'-[B,G-IMIDO] TRIPHOSPHATE

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.282 
  • R-Value Work: 0.242 

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Literature

Dynamic properties of the Ras switch I region and its importance for binding to effectors.

Spoerner, M., Herrmann, C., Vetter, I.R., Kalbitzer, H.R., Wittinghofer, A.

(2001) Proc Natl Acad Sci U S A 98: 4944-4949

  • DOI: 10.1073/pnas.081441398
  • Primary Citation of Related Structures:  
    1IAQ

  • PubMed Abstract: 

    • We have investigated the dynamic properties of the switch I region of the GTP-binding protein Ras by using mutants of Thr-35, an invariant residue necessary for the switch function. Here we show that these mutants, previously used as partial loss-of-function mutations in cell-based assays, have a reduced affinity to Ras effector proteins without Thr-35 being involved in any interaction ...

    We have investigated the dynamic properties of the switch I region of the GTP-binding protein Ras by using mutants of Thr-35, an invariant residue necessary for the switch function. Here we show that these mutants, previously used as partial loss-of-function mutations in cell-based assays, have a reduced affinity to Ras effector proteins without Thr-35 being involved in any interaction. The structure of Ras(T35S)(.)GppNHp was determined by x-ray crystallography. Whereas the overall structure is very similar to wildtype, residues from switch I are completely invisible, indicating that the effector loop region is highly mobile. (31)P-NMR data had indicated an equilibrium between two rapidly interconverting conformations, one of which (state 2) corresponds to the structure found in the complex with the effectors. (31)P-NMR spectra of Ras mutants (T35S) and (T35A) in the GppNHp form show that the equilibrium is shifted such that they occur predominantly in the nonbinding conformation (state 1). On addition of Ras effectors, Ras(T35S) but not Ras(T35A) shift to positions corresponding to the binding conformation. The structural data were correlated with kinetic experiments that show two-step binding reaction of wild-type and (T35S)Ras with effectors requires the existence of a rate-limiting isomerization step, which is not observed with T35A. The results indicate that minor changes in the switch region, such as removing the side chain methyl group of Thr-35, drastically affect dynamic behavior and, in turn, interaction with effectors. The dynamics of the switch I region appear to be responsible for the conservation of this threonine residue in GTP-binding proteins.

    Organizational Affiliation: 

    Universität Regensburg, Institut für Biophysik und Physikalische Biochemie, Universitätsstrasse 31, 93053 Regensburg, Germany.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
TRANSFORMING PROTEIN P21/H-RAS-1A, B, C166Homo sapiensMutation(s): 1 
Gene Names: HRAS OR HRAS1, HRAS, HRAS1
EC: 3.6.5.2
UniProt & NIH Common Fund Data Resources
Find proteins for P01112 (Homo sapiens)
Explore P01112 
Go to UniProtKB:  P01112
PHAROS:  P01112
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01112
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GNP
Query on GNP
Download Ideal Coordinates CCD File 
E [auth A],
G [auth B],
I [auth C]		PHOSPHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER
C10 H17 N6 O13 P3
UQABYHGXWYXDTK-UUOKFMHZSA-N		 Ligand Interaction
MG
Query on MG
Download Ideal Coordinates CCD File 
D [auth A],
F [auth B],
H [auth C]		MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.282 
  • R-Value Work: 0.242 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.89α = 90
b = 79.06β = 90
c = 94.04γ = 90
Software Package:
Software NamePurpose
AMoREphasing
CNSrefinement
MAR345data collection
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-06-06
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-04
    Changes: Refinement description
  • Version 1.4: 2021-11-10
    Changes: Database references, Derived calculations