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Updated: Mar 11, 2026

Covalent Labeling with Diethylpyrocarbonate for Studying Protein Higher-Order Structure by Mass Spectrometry
Published on: June 15, 2021
Oligomeric status of human cystathionine beta-synthase modulates AdoMet binding
Angel L Pey1, Luis Alfonso Martínez-Cruz2, Jan P Kraus3
1Department of Physical Chemistry, Faculty of Sciences, University of Granada, Spain.
Abstract:
Cystathionine beta-synthase (CBS) plays a key role in the metabolism of sulfur-containing amino acids. CBS is a multidomain tetrameric enzyme allosterically activated by S-adenosylmethionine (AdoMet). Recent crystallographic analyses of engineered CBS lacking the loop made up of residues 516-525 revealed discrepancies in AdoMet binding compared to previous biophysical studies on a full-length CBS. Here, we show that removal of the loop 516-525 functionally eliminates the high affinity sites responsible for kinetic stabilization of the full-length enzyme and yields a dimeric AdoMet-inducible enzyme, in which kinetic stabilization is now exerted by AdoMet binding to the remaining low affinity sites.
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