Crystal structure of the SpoU Methyltransferase AviRb from Streptomyces viridochromogenes

Experimental Data Snapshot

  • Resolution: 2.37 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.208 

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Structure and function of the antibiotic resistance-mediating methyltransferase AviRb from Streptomyces viridochromogenes

Mosbacher, T.G.Bechthold, A.Schulz, G.E.

(2005) J Mol Biol 345: 535-545

  • DOI: https://doi.org/10.1016/j.jmb.2004.10.051
  • Primary Citation of Related Structures:  
    1X7O, 1X7P

  • PubMed Abstract: 

    The emergence of antibiotic-resistant bacterial strains is a widespread problem in medical practice and drug design, and each case requires the elucidation of the underlying mechanism. AviRb from Streptomyces viridochromogenes methylates the 2'-O atom of U2479 of the 23S ribosomal RNA in Gram-positive bacteria and thus mediates resistance to the oligosaccharide (orthosomycin) antibiotic avilamycin. The structure of AviRb with and without bound cofactor S-adenosyl-L-methionine (AdoMet) was determined, showing that it is a homodimer belonging to the SpoU family within the SPOUT class of methyltransferases. The relationships within this class were analyzed in detail and, in addition, a novel fourth SpoU sequence fingerprint is proposed. Each subunit of AviRb consists of two domains. The N-terminal domain, being related to the ribosomal proteins L30 and L7Ae, is likely to bind RNA. The C-terminal domain is related to all SPOUT methyltransferases, and is responsible for AdoMet-binding, catalysis and dimerization. The cofactor binds at the characteristic knot of the polypeptide in an unusually bent conformation. The transferred methyl group points to a broad cleft formed with the L30-type domain of the other subunit. Measurements of mutant activity revealed four important residues responsible for catalysis and allowed the modeling of a complex between AviRb and the RNA target. The model includes a specificity pocket for uracil but does not contain a base for deprotonating the 2'-O atom of U2479 on methylation.

  • Organizational Affiliation

    Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität, Albertstr. 21, D-79104 Freiburg im Breisgau, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
rRNA methyltransferase
A, B
287Streptomyces viridochromogenesMutation(s): 0 
EC: 2.1.1
Find proteins for Q9F5K6 (Streptomyces viridochromogenes)
Explore Q9F5K6 
Go to UniProtKB:  Q9F5K6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9F5K6
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B
Experimental Data & Validation

Experimental Data

  • Resolution: 2.37 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.208 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 76.623α = 90
b = 76.623β = 90
c = 208.935γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-01-25
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.3: 2014-04-16
    Changes: Experimental preparation
  • Version 1.4: 2017-10-11
    Changes: Refinement description