The structural role of the zinc ion can be dispensable in prokaryotic zinc-finger domains

Ilaria Baglivo, Luigi Russo, Sabrina Esposito, Gaetano Malgieri, Mario Renda, Antonio Salluzzo, Benedetto Di Blasio, Carla Isernia, Roberto Fattorusso, Paolo V. Pedone

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The recent characterization of the prokaryotic Cys2His2zinc-finger domain, identified in Ros protein from Agrobacterium tumefa-ciens, has demonstrated that, although possessing a similar zinc coordination sphere, this domain is structurally very different from its eukaryotic counterpart. A search in the databases has identified ≈300 homologues with a high sequence identity to the Ros protein, including the amino acids that form the extensive hydrophobic core in Ros. Surprisingly, the Cys2His2 zinc coordination sphere is generally poorly conserved in the Ros homologues, raising the question of whether the zinc ion is always preserved in these proteins. Here, we present a functional and structural study of a point mutant of Ros protein, Ros56-142C82D, in which the second coordinating cysteine is replaced by an aspartate, 5 previ-ously-uncharacterized representative Ros homologues from Me-sorhizobium loti, and 2 mutants of the homologues. Our results indicate that the prokaryotic zinc-finger domain, which in Ros protein tetrahedrally coordinates Zn(ll) through the typical Cys2His2coordination, in Ros homologues can either exploit a CysAspHis2 coordination sphere, previously never described in DNA binding zinc finger domains to our knowledge, or lose the metal, while still preserving the DNA-binding activity. We demonstrate that this class of prokaryotic zinc-finger domains is structurally very adaptable, and surprisingly single mutations can transform a zinc-binding domain into a nonzinc-binding domain and vice versa, without affecting the DNA-binding ability. In light of our findings an evolutionary link between the prokaryotic and eukaryotic zinc-finger domains, based on bacteria-to-eukaryota horizontal gene transfer, is discussed.
Original languageEnglish
Pages (from-to)6933 - 6938
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number17
DOIs
Publication statusPublished - 28 Apr 2009
Externally publishedYes

    Fingerprint

All Science Journal Classification (ASJC) codes

  • General

Cite this

Baglivo, I., Russo, L., Esposito, S., Malgieri, G., Renda, M., Salluzzo, A., Di Blasio, B., Isernia, C., Fattorusso, R., & Pedone, P. V. (2009). The structural role of the zinc ion can be dispensable in prokaryotic zinc-finger domains. Proceedings of the National Academy of Sciences of the United States of America, 106(17), 6933 - 6938. https://doi.org/10.1073/pnas.0810003106