3ASY

ligand-free structure of uridine kinase from thermus thermophilus HB8


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.299 
  • R-Value Work: 0.233 

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This is version 1.1 of the entry. See complete history


Literature

A Single Amino Acid Limits the Substrate Specificity of Thermus thermophilus Uridine-Cytidine Kinase to Cytidine

Tomoike, F.Nakagawa, N.Kuramitsu, S.Masui, R.

(2011) Biochemistry 50: 4597-4607

  • DOI: 10.1021/bi102054n
  • Primary Citation of Related Structures:  
    3ASY, 3ASZ

  • PubMed Abstract: 
  • The salvage pathways of nucleotide biosynthesis are more diverse and are less well understood as compared with de novo pathways. Uridine-cytidine kinase (UCK) is the rate-limiting enzyme in the pyrimidine-nucleotide salvage pathway. In this study, we have characterized a UCK homologue of Thermus thermophilus HB8 (ttCK) biochemically and structurally ...

    The salvage pathways of nucleotide biosynthesis are more diverse and are less well understood as compared with de novo pathways. Uridine-cytidine kinase (UCK) is the rate-limiting enzyme in the pyrimidine-nucleotide salvage pathway. In this study, we have characterized a UCK homologue of Thermus thermophilus HB8 (ttCK) biochemically and structurally. Unlike other UCKs, ttCK had substrate specificity toward only cytidine and showed no inhibition by UTP, suggesting uridine does not bind to ttCK as substrate. Structural analysis revealed that the histidine residue located near the functional group at position 4 of cytidine or uridine in most UCKs is substituted with tyrosine, Tyr93, in ttCK. Replacement of Tyr93 by histidine or glutamine endowed ttCK with phosphorylation activity toward uridine. These results suggested that a single amino acid residue, Tyr93, gives cytidine-limited specificity to ttCK. However, replacement of Tyr93 by Phe or Leu did not change the substrate specificity of ttCK. Therefore, we conclude that a residue at this position is essential for the recognition of uridine by UCK. In addition, thymidine phosphorylase from T. thermophilus HB8 was equally active with thymidine and uridine, which indicates that this protein is the sole enzyme metabolizing uridine in T. Thermophilus HB8. On the basis of these results, we discuss the pyrimidine-salvage pathway in T. thermophilus HB8.


    Organizational Affiliation

    Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, Japan.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Uridine kinaseA, B211Thermus thermophilus HB8Mutation(s): 0 
Gene Names: udkTTHA0578
EC: 2.7.1.48
UniProt
Find proteins for Q5SKR5 (Thermus thermophilus (strain ATCC 27634 / DSM 579 / HB8))
Explore Q5SKR5 
Go to UniProtKB:  Q5SKR5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ5SKR5
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.299 
  • R-Value Work: 0.233 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.364α = 90
b = 70.364β = 90
c = 179.243γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-06-01
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance