3RSB

Structure of the Archaeal GTP:AdoCbi-P Guanylyltransferase (CobY) from Methanocaldococcus jannaschii


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.279 
  • R-Value Work: 0.256 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structure and Mutational Analysis of the Archaeal GTP:AdoCbi-P Guanylyltransferase (CobY) from Methanocaldococcus jannaschii: Insights into GTP Binding and Dimerization.

Newmister, S.A.Otte, M.M.Escalante-Semerena, J.C.Rayment, I.

(2011) Biochemistry 50: 5301-5313

  • DOI: 10.1021/bi200329t

  • PubMed Abstract: 
  • In archaea and bacteria, the late steps in adenosylcobalamin (AdoCbl) biosynthesis are collectively known as the nucleotide loop assembly (NLA) pathway. In the archaeal and bacterial NLA pathways, two different guanylyltransferases catalyze the activ ...

    In archaea and bacteria, the late steps in adenosylcobalamin (AdoCbl) biosynthesis are collectively known as the nucleotide loop assembly (NLA) pathway. In the archaeal and bacterial NLA pathways, two different guanylyltransferases catalyze the activation of the corrinoid. Structural and functional studies of the bifunctional bacterial guanylyltransferase that catalyze both ATP-dependent corrinoid phosphorylation and GTP-dependent guanylylation are available, but similar studies of the monofunctional archaeal enzyme that catalyzes only GTP-dependent guanylylation are not. Herein, the three-dimensional crystal structure of the guanylyltransferase (CobY) enzyme from the archaeon Methanocaldococcus jannaschii (MjCobY) in complex with GTP is reported. The model identifies the location of the active site. An extensive mutational analysis was performed, and the functionality of the variant proteins was assessed in vivo and in vitro. Substitutions of residues Gly8, Gly153, or Asn177 resulted in ≥94% loss of catalytic activity; thus, variant proteins failed to support AdoCbl synthesis in vivo. Results from isothermal titration calorimetry experiments showed that MjCobY(G153D) had 10-fold higher affinity for GTP than MjCobY(WT) but failed to bind the corrinoid substrate. Results from Western blot analyses suggested that the above-mentioned substitutions render the protein unstable and prone to degradation; possible explanations for the observed instability of the variants are discussed within the framework of the three-dimensional crystal structure of MjCobY(G153D) in complex with GTP. The fold of MjCobY is strikingly similar to that of the N-terminal domain of Mycobacterium tuberculosis GlmU (MtbGlmU), a bifunctional acetyltransferase/uridyltransferase that catalyzes the formation of uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc).


    Organizational Affiliation

    Department of Biochemistry, University of Wisconsin , Madison, WI 53706, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Adenosylcobinamide-phosphate guanylyltransferase
A, B, C, D
196Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440)Mutation(s): 1 
Gene Names: cobY
EC: 2.7.7.62
Find proteins for Q58517 (Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440))
Go to UniProtKB:  Q58517
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GTP
Query on GTP

Download SDF File 
Download CCD File 
A, B, C, D
GUANOSINE-5'-TRIPHOSPHATE
C10 H16 N5 O14 P3
XKMLYUALXHKNFT-UUOKFMHZSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B, C, D
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
GTPKd: 400 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.279 
  • R-Value Work: 0.256 
  • Space Group: P 31
Unit Cell:
Length (Å)Angle (°)
a = 63.600α = 90.00
b = 63.600β = 90.00
c = 222.500γ = 120.00
Software Package:
Software NamePurpose
REFMACrefinement
HKL-3000data reduction
HKL-3000data collection
SOLVEphasing
HKL-3000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-05-18
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance