Structural phylogenomics uncovers the early and concurrent origins of cysteine biosynthesis and iron-sulfur proteins

Hong Yu Zhang, Tao Qin, Ying Ying Jiang, Gustavo Caetano-Anollés

Research output: Contribution to journalArticlepeer-review

Abstract

Cysteine (Cys) has unique chemical properties of catalysis, metal chelation, and protein stabilization. While Cys biosynthesis is assumed to be very ancient, the actual time of origin of these metabolic pathways remains unknown. Here, we use the molecular clocks of protein folds and fold superfamilies to time the origin of Cys biosynthesis. We find that the tRNA-dependent biosynthetic pathway appeared ~3.5 billion years ago while the tRNA-independent counterpart emerged ~500 million years later. A deep analysis of the origins of Cys biosynthesis in the context of emerging biochemistry uncovers some intriguing features of the planetary environment of early Earth. Results suggest that iron-sulfur (Fe-S) proteins that use cysteinyl sulfur to bind iron atoms were not the first to arise in evolution. Instead, their origin coincides with the appearance of the first Cys biosynthetic pathway. It is therefore likely that Cys did not play an important role in the make up of primordial protein molecules and that Fe-S clusters were not part of active sites at the beginning of biological history.

Original languageEnglish (US)
Pages (from-to)542-545
Number of pages4
JournalJournal of Biomolecular Structure and Dynamics
Volume30
Issue number5
DOIs
StatePublished - Sep 6 2012

Keywords

  • Cysteine biosynthesis
  • Evolution
  • Iron-sulfur proteins
  • Molecular clock
  • Protein structure

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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