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Voltammetry of a ‘protein on a rope’
Author(s) -
Baymann Frauke,
Barlow Nicola L,
Aubert Corinne,
Schoepp-Cothenet Barbara,
Leroy Gisele,
Armstrong Fraser A
Publication year - 2003
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 - 10.1016/s0014-5793(03)00206-0
Subject(s) - aquifex aeolicus , electron transfer , cytochrome c , chemistry , periplasmic space , rope , cysteine , covalent bond , crystallography , stereochemistry , photochemistry , escherichia coli , biochemistry , organic chemistry , mitochondrion , structural engineering , engineering , gene , enzyme
A periplasmic electron‐transfer protein, cytochrome c 555 m from Aquifex aeolicus contains a 62‐residue N‐terminal extension by which it is anchored to the membrane – most probably via a thioester bond to its N‐terminal cysteine. This linker can act as a ‘rope’ to tether the protein close to its reaction partners. Mimicking this principle, a recombinant cytochrome c 555 m , expressed in Escherichia coli , has been attached covalently to a gold electrode modified with 6‐mercaptohexan‐1‐ol. The ‘tethered’ cytochrome c 555 m displays remarkably fast electron‐transfer kinetics, with an electrochemical exchange rate constant k 0 of 1.4×10 4 s −1 . The results show that fast electron transfer is associated with weak interactions: importantly, the tethered cytochrome can explore many different orientations without escaping into solution.