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Cation‐ and peptide‐binding properties of human centrin 2
Author(s) -
Durussel Isabelle,
Blouquit Yves,
Middendorp Sandrine,
Craescu Constantin T.,
Cox Jos A.
Publication year - 2000
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(00)01452-6
Subject(s) - melittin , chemistry , calmodulin , monomer , cooperativity , peptide , dimer , biophysics , cooperative binding , binding site , biochemistry , stereochemistry , biology , enzyme , organic chemistry , polymer
Centrin and calmodulin (CaM) are closely related four‐EF‐hand Ca 2+ ‐binding proteins. While CaM is monomeric, centrin 2 is dimeric and binds only two Ca 2+ per dimer, likely to site IV in each monomer. Ca 2+ binding to centrin 2 displays pronounced negative cooperativity and a [Ca 2+ ] 0.5 of 30 μM. As in CaM, Ca 2+ binding leads to the exposure of a hydrophobic probe‐accessible patch on the surface of centrin 2. Provided Ca 2+ is present, centrin 2 forms a 1:1 peptide:monomer complex with melittin with an affinity of 100 nM. The complex binds four instead of two Ca 2+ . Our data point to surprising differences in the mode of activation of these homologous proteins.