1R8G

Structure and function of YbdK


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

YbdK is a carboxylate-amine ligase with a gamma-glutamyl:Cysteine ligase activity: crystal structure and enzymatic assays

Lehmann, C.Doseeva, V.Pullalarevu, S.Krajewski, W.Howard, A.Herzberg, O.

(2004) PROTEINS: STRUCT.,FUNCT.,GENET. 56: 376-383

  • DOI: 10.1002/prot.20103

  • PubMed Abstract: 
  • The Escherichia coli open reading frame YbdK encodes a member of a large bacterial protein family of unknown biological function. The sequences within this family are remotely related to the sequence of gamma-glutamate-cysteine ligase (gamma-GCS), an ...

    The Escherichia coli open reading frame YbdK encodes a member of a large bacterial protein family of unknown biological function. The sequences within this family are remotely related to the sequence of gamma-glutamate-cysteine ligase (gamma-GCS), an enzyme in the glutathione biosynthetic pathway. A gene encoding gamma-GCS in E. coli is already known. The 2.15 A resolution crystal structure of YbdK reveals an overall fold similar to that of glutamine synthetase (GS), a nitrogen metabolism enzyme that ligates glutamate and ammonia to yield glutamine. GS and gamma-GCS perform related chemical reactions and require ATP and Mg2+ for their activity. The Mg2+-dependent binding of ATP to YbdK was confirmed by fluorescence spectroscopy employing 2'(or 3')-O-(trinitrophenyl)adenosine 5'-triphosphate, and yielding a dissociation constant of 3 +/- 0.5 microM. The structure of YbdK contains a crevice that corresponds to the binding sites of ATP, Mg2+ and glutamate in GS. Many of the GS residues that coordinate the metal ions and interact with glutamic acid and the phosphoryl and ribosyl groups of ATP are also present in YbdK. GS amino acids that have been associated with ammonia binding have no obvious counterparts in YbdK, consistent with a substrate specificity that is different from that of GS. Ligase activity between glutamic acid and each of the twenty amino acid residues was tested on high performance liquid chromatography (HPLC) by following the hydrolysis of ATP to ADP. Catalysis was observed only with cysteine. A pyruvate kinase/lactic acid dehydrogenase coupled assay was used to rule out GS activity and to determine that YbdK exhibits gamma-GCS activity. The catalytic rate was found to be approximately 500-fold slower than that reported for authentic gamma-GCS.


    Organizational Affiliation

    Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, Maryland 20850, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Hypothetical protein ybdK
A, B
372Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: ybdK
EC: 6.3.2.2
Find proteins for P77213 (Escherichia coli (strain K12))
Go to UniProtKB:  P77213
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.189 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 49.470α = 90.00
b = 100.320β = 99.94
c = 71.370γ = 90.00
Software Package:
Software NamePurpose
RESOLVEphasing
HKL-2000data collection
HKL-2000data reduction
CNSrefinement
RESOLVEmodel building
HKL-2000data scaling
SOLVEphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-08-17
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance