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A synthetic analogue for the active site of plant‐type ferredoxin: Two different coordination isomers by a four‐Cys‐containing [20]‐peptide
Author(s) -
Ueyama Norikazu,
Ueno Satoru,
Nakamura Akira,
Wada Keishiro,
Matsubara Hiroshi,
Kumagai ShinIchiro,
Sakakibara Shumpei,
Tsukihara Tomitake
Publication year - 1992
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360321111
Subject(s) - chemistry , ferredoxin , redox , ligand (biochemistry) , stereochemistry , peptide , electrochemistry , dimethylformamide , coordination complex , amino acid , crystallography , inorganic chemistry , receptor , metal , electrode , organic chemistry , biochemistry , enzyme , solvent
The (Fe 2 S 2 ) 2+ complex of an artificial 20‐peptide ligand, Ac‐Pro‐Tyr‐Ser‐ Cys ‐Arg‐Ala‐Gly‐Ala‐ Cys ‐Ser‐Thr‐ Cys ‐Ala‐Gly‐Pro‐Leu‐Leu‐Thr‐Cys‐Val‐NH 2 , containing an invariant Cys‐A‐B‐C‐D‐Cys‐X‐Y‐Cys (A, B, C, D, X, Y = amino acid residues) fragment of plant‐type ferredoxins was synthesized by a ligand exchange method with [Fe 2 S 2 (S‐ t ‐Bu) 4 ] 2− . 1 H‐nmr spectroscopic and electrochemical data of the complex indicate the presence of two coordination isomers. One of them having a Cys‐X‐Y‐Cys bridging coordination to the two Fe(III) ions, has the (Fe 2 S 2 ) 2+ core environment similar to those of the denatured plant‐type ferredoxins and exhibits a positive shifted redox potential at −0.64 V vs saturated colonel electrode (SCE) in N,N ‐dimethylformamide (DMF). Another isomer with the Cys‐A‐B‐C‐D‐Cys bridging coordination shows a negative redox potential at −0.96 V vs SCE in DMF. © 1992 John Wiley & Sons, Inc.