Characterisation of the effects of mutation of the caldesmon sequence 691glu‐trp‐leu‐thr‐lys‐thr696 to pro‐gly‐his‐tyr‐asn‐asn on caldesmon‐calmodulin interaction

FEBS Letters

EL-Mezgueldi, Mohammed²  Marston, Steven B²  Copeland, O'neal²  Huber, Pia A.J²  Levine, Barry A¹ 

[1] School of Biochemistry, University of Birmingham, Birmingham B15 2TT, UK;Imperial College School of Medicine at the National Heart and Lung Institute, Cardiac Medicine, Dovehouse Street, London SW3 6LY, UK

关键词: Caldesmon;    Calmodulin;    Smooth muscle;    NMR;    Tryptophan fluorescence;    Actin;    Tropomyosin;    Regulation;    S-1;    chymotryptic myosin subfragment-1;    EGTA;    ethylene glycol-O;    O′-bis(2-aminoethyl)-N;    N;    N′;    N′-tetraacetic acid;    DTT;    1;    4-dithio-dl-threitol;    PAGE;    polyacrylamide gel electrophoresis;    SDS;    sodium dodecyl sulphate;   

DOI  :  10.1016/S0014-5793(98)00071-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have investigated the functional properties of a mutant (Cg1) derived from the C-terminal 99 amino acids of chicken caldesmon, 658–756 (658C) where the sequence ⁶⁹¹glu-trp-leu-thr-lys-thr⁶⁹⁶ is changed to pro-gly-his-tyr-asn-asn. Cg1 bound Ca²⁺-calmodulin with (1/7)th of the affinity as compared to 658C or whole caldesmon. NMR titrations indicate that the contacts of Ca²⁺-calmodulin with the Trp-722 region of the peptide are retained but that those at the mutated site are lost. Most importantly Ca²⁺-calmodulin is not able to reverse the Cg1-induced inhibition. We conclude that the interaction of calmodulin with this caldesmon sequence is crucial for the reversal of caldesmon inhibition of actin-tropomyosin activation of myosin ATPase. The results are interpreted in terms of multi-site attachment of actin and Ca²⁺-calmodulin to overlapping sequences in caldesmon domain 4b.

【 授权许可】

Unknown