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Updated: May 3, 2026

Profiling of Methyltransferases and Other S-adenosyl-L-homocysteine-binding Proteins by Capture Compound Mass Spectrometry CCMS
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Structure of an unusual S-adenosylmethionine synthetase from Campylobacter jejuni

Stephen P Zano1, Alexander G Pavlovsky1, Ronald E Viola1

  • 1Department of Chemistry, The University of Toledo, Toledo, OH 43606, USA.

Acta Crystallographica. Section D, Biological Crystallography
|February 18, 2014
PubMed

Insights

S-Adenosylmethionine (AdoMet) is crucial for bacterial virulence. The unique structure of Campylobacter jejuni AdoMet synthetase (cjMAT) explains its high activity and altered substrate use, offering insights into enzyme evolution.

Area of Science:

  • Biochemistry
  • Enzymology
  • Microbial Pathogenesis

Background:

  • S-Adenosylmethionine (AdoMet) is a vital cofactor in biological methylation and group-transfer reactions.
  • AdoMet also acts as a precursor for quorum-sensing molecules regulating virulence in Gram-negative bacteria.
  • AdoMet synthetases (MATs) catalyze AdoMet synthesis, with homologs found across diverse species.

Purpose of the Study:

  • To investigate the structural and functional characteristics of AdoMet synthetase from Campylobacter jejuni (cjMAT).
  • To understand why cjMAT exhibits unusual properties compared to other bacterial MATs.
  • To elucidate the structural basis for cjMAT's higher catalytic activity and altered substrate kinetics.

Main Methods:

  • Comparative sequence analysis of cjMAT against other MATs.
  • Structural elucidation of cjMAT, focusing on quaternary structure and active-site features.
  • Kinetic analysis of cjMAT with various substrates.

Main Results:

  • cjMAT displays lower sequence identity and significant structural differences (insertions, substitutions) compared to other bacterial MATs.
  • cjMAT possesses a unique dimeric quaternary structure, distinct from the typical monomeric or tetrameric forms of other MATs.
  • cjMAT exhibits higher catalytic activity and altered substrate preferences, attributed to its unique structure and active-site modifications.

Conclusions:

  • The distinct structure of cjMAT explains its outlier status and enhanced kinetic properties.
  • Structural alterations in cjMAT provide insights into enzyme adaptation and evolution.
  • Understanding cjMAT's unique characteristics can inform strategies targeting bacterial virulence mechanisms.
Keywords:
Campylobacter jejuniS-adenosylmethionine synthetasedimeric structuresubunit asymmetry

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