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Selectivity in heavy metal‐ binding to peptides and proteins
Author(s) -
DeSilva Tara M.,
Veglia Gianluigi,
Porcelli Fernando,
Prantner Andrew M.,
Opella Stanley J.
Publication year - 2002
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.10149
Subject(s) - chemistry , affinities , peptide , metal , binding affinities , stereochemistry , residue (chemistry) , structural motif , binding site , mercury (programming language) , crystallography , biochemistry , receptor , organic chemistry , computer science , programming language
The metal‐binding affinities and three‐dimensional structures of three synthetic 18‐residue peptides with sequences derived from that of the highly conserved metal‐binding motif MXCXXC found in many heavy metal‐binding proteins were determined. A change in register of the cysteines and alanines of the sequence from the periplasmic mercury‐binding protein, MerP, i.e., CAAC, CACA, and CCAA, affects the specificity of metal binding, in particular, the peptide with vicinal cysteines binds only mercury. The three‐dimensional structures of the mercury‐bound forms of the three peptides determined in solution by NMR spectroscopy peptides differ considerably, even though they are all linear bicoordinate complexes. The three‐dimensional structure of the peptide with CAAC bound to Cd(II) demonstrates that the metal‐binding loop is malleable enough to accommodate modes of coordination other than linear bicoordinate. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 189–197, 2002