1SD0

Structure of arginine kinase C271A mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.210 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Literature

The active site cysteine of arginine kinase: structural and functional analysis of partially active mutants

Gattis, J.L.Ruben, E.Fenley, M.O.Ellington, W.R.Chapman, M.S.

(2004) Biochemistry 43: 8680-8689

  • DOI: https://doi.org/10.1021/bi049793i
  • Primary Citation of Related Structures:  
    1SD0

  • PubMed Abstract: 

    Arginine kinase buffers cellular ATP levels by catalyzing reversible phosphoryl transfer between ATP and arginine. A conserved cysteine has long been thought important in catalysis. Here, cysteine 271 of horseshoe crab arginine kinase has been mutated to serine, alanine, asparagine, or aspartate. Catalytic turnover rates were 0.02-1.0% of wild type, but the activity of uncharged mutations could be partially rescued with chloride. Steady-state binding constants were slightly increased, more so for phospho-L-arginine than ADP. Substrate binding synergy observed in many phosphagen kinases was reduced or eliminated in mutant enzymes. The crystallographic structure of the alanine mutant at 2.3 A resolution, determined as a transition state analogue complex with arginine, nitrate, and MgADP, was nearly identical to wild type. Enzyme-substrate interactions are maintained as in wild type, and substrates remain at least roughly aligned for in-line phosphoryl transfer. Homology models with serine, asparagine, or aspartate replacing the active site cysteine similarly show only minor structural changes. Most striking, however, is the presence in the C271A mutant crystallographic structure of a chloride ion within 3.5 A of the nonreactive N(eta) substrate nitrogen, approximating the position of the sulfur in the wild-type's cysteine. Together, the results contradict prevailing speculation that the cysteine mediates a substrate-induced conformational change, confirm that it is the thiolate form that is relevant to catalysis, and suggest that one of its roles is to help to enhance the catalytic rate through electrostatic stabilization of the transition state.


  • Organizational Affiliation

    Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4380, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Arginine kinase357Limulus polyphemusMutation(s): 1 
Gene Names: ak
EC: 2.7.3.3
UniProt
Find proteins for P51541 (Limulus polyphemus)
Explore P51541 
Go to UniProtKB:  P51541
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP51541
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
ADP
Query on ADP

Download Ideal Coordinates CCD File 
F [auth A]ADENOSINE-5'-DIPHOSPHATE
C10 H15 N5 O10 P2
XTWYTFMLZFPYCI-KQYNXXCUSA-N
ARG
Query on ARG

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E [auth A]ARGININE
C6 H15 N4 O2
ODKSFYDXXFIFQN-BYPYZUCNSA-O
NO3
Query on NO3

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B [auth A]NITRATE ION
N O3
NHNBFGGVMKEFGY-UHFFFAOYSA-N
CL
Query on CL

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D [auth A]CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
MG
Query on MG

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C [auth A]MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.210 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 64.905α = 90
b = 71.255β = 90
c = 79.98γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSrefinement
CNSphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-07-27
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-10-27
    Changes: Database references, Derived calculations
  • Version 1.4: 2023-08-23
    Changes: Data collection, Refinement description