Persulfide Formation Mediates Cysteine and Homocysteine Biosynthesis in Methanosarcina acetivorans

The mechanisms of sulfur uptake and trafficking in methanogens inhabiting sulfidic environments are highly distinctive. In aerobes, sulfur transfers between proteins occur via persulfide relay, but direct evidence for persulfides in methanogens has been lacking. Here, we use mass spectrometry to ana...

Full description

Saved in:
Bibliographic Details
Published in:Biochemistry (Easton) 2017-02, Vol.56 (8), p.1051-1061
Main Authors: Rauch, Benjamin J, Klimek, John, David, Larry, Perona, John J
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Amino Acyl-tRNA Synthetases - chemistry
Amino Acyl-tRNA Synthetases - metabolism
Biocatalysis
Cysteine - biosynthesis
Cysteine - chemistry
Homocysteine - biosynthesis
Homocysteine - chemistry
Methanosarcina - metabolism
Peptides - chemistry
Peptides - metabolism
Sulfides - chemistry
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The mechanisms of sulfur uptake and trafficking in methanogens inhabiting sulfidic environments are highly distinctive. In aerobes, sulfur transfers between proteins occur via persulfide relay, but direct evidence for persulfides in methanogens has been lacking. Here, we use mass spectrometry to analyze tryptic peptides of the Methanosarcina acetivorans SepCysS and MA1821 proteins purified anaerobically from methanogen cells. These enzymes insert sulfide into phosphoseryl­(Sep)-tRNACys and aspartate semialdehyde, respectively, to form Cys-tRNACys and homocysteine. A high frequency of persulfidation at conserved cysteines of each protein was identified, while the substantial presence of persulfides in peptides from other cellular proteins suggests that this modification plays a general physiological role in the organism. Purified native SepCysS containing persulfide at conserved Cys260 generates Cys-tRNACys in anaerobic single-turnover reactions without exogenously added sulfur, directly linking active-site persulfide formation in vivo with catalytic activity.
ISSN:0006-2960
1520-4995
DOI:10.1021/acs.biochem.6b00931