JBIC Journal of Biological Inorganic Chemistry

, Volume 13, Issue 2, pp 157–170

Iron–sulfur protein folds, iron–sulfur chemistry, and evolution

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DOI: 10.1007/s00775-007-0318-7

Cite this article as:
Meyer, J. J Biol Inorg Chem (2008) 13: 157. doi:10.1007/s00775-007-0318-7

Abstract

An inventory of unique local protein folds around Fe–S clusters has been derived from the analysis of protein structure databases. Nearly 50 such folds have been identified, and over 90% of them harbor low-potential [2Fe–2S]2+,+ or [4Fe–4S]2+,+ clusters. In contrast, high-potential Fe–S clusters, notwithstanding their structural diversity, occur in only three different protein folds. These observations suggest that the extant population of Fe–S protein folds has to a large extent been shaped in the reducing iron- and sulfur-rich environment that is believed to have predominated on this planet until approximately two billion years ago. High-potential active sites are then surmised to be rarer because they emerged later, in a more oxidizing biosphere, in conditions where iron and sulfide had become poorly available, Fe–S clusters were less stable, and in addition faced competition from heme iron and copper active sites. Among the low-potential Fe–S active sites, protein folds hosting [4Fe–4S]2+,+ clusters outnumber those with [2Fe–2S]2+,+ ones by a factor of 3 at least. This is in keeping with the higher chemical stability and versatility of the tetranuclear clusters, compared with the binuclear ones. It is therefore suggested that, at least while novel Fe–S sites are evolving within proteins, the intrinsic chemical stability of the inorganic moiety may be more important than the stabilizing effect of the polypeptide chain. The discovery rate of novel Fe–S-containing protein folds underwent a sharp increase around 1995, and has remained stable to this day. The current trend suggests that the mapping of the Fe–S fold space is not near completion, in agreement with predictions made for protein folds in general. Altogether, the data collected and analyzed here suggest that the extant structural landscape of Fe–S proteins has been shaped to a large extent by primeval geochemical conditions on one hand, and iron–sulfur chemistry on the other.

Keywords

Ferredoxin Rubredoxin Hydrogenase Iron–sulfur Bioenergetics Evolution 

Abbreviations

CoA

coenzyme A

EPR

electron paramagnetic resonance

Fd

ferredoxin

FNR

fumarate nitrate regulator

GABA

γ-aminobutyric acid

HiPIP

high potential iron protein

PDB

Protein Data Bank

PRPP

phosphoribosylpyrophosphate

Rd

rubredoxin

tRNA

transfer RNA

Copyright information

© SBIC 2007

Authors and Affiliations

  1. 1.Laboratoire de Chimie et Biologie des MétauxIRTSV, Commissariat à l’Energie Atomique/CNRS/Université Joseph FourierGrenobleFrance

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