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NMR studies of the interaction between inner membrane‐associated and periplasmic cytochromes from Geobacter sulfurreducens
Author(s) -
Dantas Joana M.,
Brausemann Anton,
Einsle Oliver,
Salgueiro Carlos A.
Publication year - 2017
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.12695
Subject(s) - geobacter sulfurreducens , periplasmic space , chemistry , heme , electron transfer , cytochrome , dissociation constant , cytochrome c , bacterial outer membrane , biochemistry , inner membrane , biophysics , membrane , enzyme , bacteria , mitochondrion , biology , photochemistry , receptor , escherichia coli , biofilm , gene , genetics
Geobacter sulfurreducens is a dissimilatory metal‐reducing bacterium with notable properties and significance in biotechnological applications. Biochemical studies suggest that the inner membrane‐associated diheme cytochrome MacA and the periplasmic triheme cytochrome PpcA from G. sulfurreducens can exchange electrons. In this work, NMR chemical shift perturbation measurements were used to map the interface region and to measure the binding affinity between PpcA and MacA. The results show that MacA binds to PpcA in a cleft defined by hemes I and IV, favoring the contact between PpcA heme IV and the MacA high‐potential heme. The dissociation constant values indicate the formation of a low‐affinity complex between the proteins, which is consistent with the transient interaction observed in electron transfer complexes.