Premium
Click Chemistry with an Active Site Variant of Azurin
Author(s) -
de Jongh Thyra E.,
van Roon AnneMarie M.,
Prudêncio Miguel,
Ubbink Marcellus,
Canters Gerard W.
Publication year - 2006
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200600574
Subject(s) - chemistry , dimer , active site , imidazole , ligand (biochemistry) , azurin , stereochemistry , crystallography , electron transfer , photochemistry , catalysis , organic chemistry , biochemistry , receptor
The active site of the blue copper protein azurin (Azu) from Pseudomonas aeruginosa consists of a Cu ion immobilized by bonds to four amino acid side chains. The protein assists in electron transfer in vivo . Replacement of Cu‐ligand His117 by a Gly makes the Cu site accessible for exogenous ligands. Incubation of the H117G Azu with n ‐alkane linkers carrying imidazole groups at opposite ends leads to the formation of noncovalently linked Azu dimers. The active site of H117G Azu is vulnerable to Cu‐catalyzed oxidative attack. Replacement of Cu II by Zn II leads to stable dimers, whose structures have been determined by X‐ray diffraction. These structures are reported here. The similarity in the structure of the active site between the wild type ( wt ) Zn‐Azu and the dimer is remarkable in light of the different relation of the coordinating imidazole to the protein framework (covalently attached vs. exogenous origin, respectively). The part of the “ligand loop” running from amino acid 116 to 121 has acquired increased flexibility in the mutant. The connected subunits have adopted an unexpected orientation relative to each other.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)