Characterization of a Novel Porin-Like Protein, ExtI, from Geobacter sulfurreducens and Its Implication in the Reduction of Selenite and Tellurite

Autor: Mst. Ishrat Jahan, Ryuta Tobe, Hisaaki Mihara
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: International Journal of Molecular Sciences, Vol 19, Iss 3, p 809 (2018)
Druh dokumentu: article
ISSN: 1422-0067
94885583
DOI: 10.3390/ijms19030809
Popis: The extI gene in Geobacter sulfurreducens encodes a putative outer membrane channel porin, which resides within a cluster of extHIJKLMNOPQS genes. This cluster is highly conserved across the Geobacteraceae and includes multiple putative c-type cytochromes. In silico analyses of the ExtI sequence, together with Western blot analysis and proteinase protection assays, showed that it is an outer membrane protein. The expression level of ExtI did not respond to changes in osmolality and phosphate starvation. An extI-deficient mutant did not show any significant impact on fumarate or Fe(III) citrate reduction or sensitivity to β-lactam antibiotics, as compared with those of the wild-type strain. However, extI deficiency resulted in a decreased ability to reduce selenite and tellurite. Heme staining analysis revealed that extI deficiency affects certain heme-containing proteins in the outer and inner membranes, which may cause a decrease in the ability to reduce selenite and tellurite. Based on these observations, we discuss possible roles for ExtI in selenite and tellurite reduction in G. sulfurreducens.
Databáze: Directory of Open Access Journals
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