ExoMeg1: a new exonuclease from metagenomic library

Author(s)

Silva-Portela, Rita C. B. ^[1] ; Carvalho, Fabiola M. ^[1] ; Pereira, Carolina P. M. ^[2] ; de Souza-Pinto, Nadja C. ^[2] ; Modesti, Mauro ^{[3, 4, 5]} ; Fuchs, Robert P. ^{[4, 5, 6, 7]} ; Agnez-Lima, Lucymara F. ^[1]

Affiliation

^[1] Univ Fed Rio Grande do Norte, Ctr Biociencias, Dept Biol Celular & Gent, BR-59072970 Natal, RN - Brazil

^[2] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-01498 Sao Paulo - Brazil

^[3] NHEJ & Maintenance Genom Integr CNRS, UMR7258, Homologous Recombinat, F-13009 Marseille - France

^[4] CRCM, INSERM, U1068, F-13009 Marseille - France

^[5] Inst J Paoli I Calmettes, F-13009 Marseille - France

^[6] Team DNA Damage Tolerance CNRS, UMR7258, F-13009 Marseille - France

^[7] Aix Marseille Univ, UM 105, F-13284 Marseille - France

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 6, JAN 27 2016.
• Web of Science Citations: 4

Abstract

DNA repair mechanisms are responsible for maintaining the integrity of DNA and are essential to life. However, our knowledge of DNA repair mechanisms is based on model organisms such as Escherichia coli, and little is known about free living and uncultured microorganisms. In this study, a functional screening was applied in a metagenomic library with the goal of discovering new genes involved in the maintenance of genomic integrity. One clone was identified and the sequence analysis showed an open reading frame homolog to a hypothetical protein annotated as a member of the Exo\_Endo\_Phos superfamily. This novel enzyme shows 3'-5' exonuclease activity on single and double strand DNA substrates and it is divalent metal-dependent, EDTA-sensitive and salt resistant. The clone carrying the hypothetical ORF was able to complement strains deficient in recombination or base excision repair, suggesting that the new enzyme may be acting on the repair of single strand breaks with 3' blockers, which are substrates for these repair pathways. Because this is the first report of an enzyme obtained from a metagenomic approach showing exonuclease activity, it was named ExoMeg1. The metagenomic approach has proved to be a useful tool for identifying new genes of uncultured microorganisms. (AU)

• FAPESP's process: 10/51906-1 - Mitochondrial bioenergetics, ion transport, redox state and DNA metabolism
• Grantee: Alicia Juliana Kowaltowski
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 08/57721-3 - Redoxome
• Grantee: Ohara Augusto
• Support Opportunities: Research Projects - Thematic Grants