GSU1771 regulates extracellular electron transfer and electroactive biofilm formation in Geobacter sulfurreducens: Genetic and electrochemical characterization.
Bioelectrochemistry
; 145: 108101, 2022 Jun.
Article
in En
| MEDLINE
| ID: mdl-35334296
ABSTRACT
Type IV pili and the >100c-type cytochromes in Geobacter sulfurreducens are essential for extracellular electron transfer (EET) towards metal oxides and electrodes. A previous report about a mutation in the gsu1771 gene indicated an enhanced reduction of insoluble Fe(III) oxides coupled with increased pilA expression. Herein, a marker-free gsu1771-deficient mutant was constructed and characterized to assess the role of this regulator in EET and the formation of electroactive biofilms. Deleting this gene delayed microbial growth in the acetate/fumarate media (electron donor and acceptor, respectively). However, this mutant reduced soluble and insoluble Fe(III) oxides more efficiently. Heme staining, western blot, and RT-qPCR analyses demonstrated that GSU1771 regulates the transcription of several genes (including pilA) and many c-type cytochromes involved in EET, suggesting the broad regulatory role of this protein. DNA-protein binding assays indicated that GSU1771 directly regulates the transcription of pilA, omcE, omcS, and omcZ. Additionally, gsu1771-deficient mutant biofilms are thicker than wild-type strains. Electrochemical studies revealed that the current produced by this biofilm was markedly higher than the wild-type strains (approximately 100-fold). Thus, demonstrating the role of GSU1771 in the EET pathway and establishing a methodology to develop highly electroactive G. sulfurreducens mutants.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacterial Proteins
/
Ferric Compounds
/
Geobacter
Language:
En
Journal:
Bioelectrochemistry
Journal subject:
BIOQUIMICA
Year:
2022
Document type:
Article
Publication country:
HOLANDA
/
HOLLAND
/
NETHERLANDS
/
NL
/
PAISES BAJOS
/
THE NETHERLANDS