Different actin affinities of human cardiac essential myosin light chain isoforms

FEBS Letters

Haase, H¹  Morano, I¹ 

[1] Max-Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13122 Berlin-Buch, Germany

关键词: Myosin light chain;    Actin;    Cardiac muscle;   

DOI  :  10.1016/S0014-5793(97)00390-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The N terminus of myosin light chain 1 (MLC-1) of skeletal muscle bind to the C terminus of actin. We investigated whether the N termini of human cardiac MLC-1 isoforms likewise bind to actin. Furthermore, we investigated whether the N-terminal sequence 5–15 (P5–14) of MLC-1 of human atrium (ALC-1) and ventricle (VLC-1) bind with different affinities to actin. Affinity beads were produced by covalently coupling a synthetic peptide corresponding to the N-terminal sequence 4–14 of human VLC-1 to aminohexylagarose in order to bind G-actin. We found, that G-actin specifically binds to the affinity beads. Furthermore, preincubation of G-actin with P5-14 of both ALC-1 and VLC-1 decreased the amount of G-actin recovered from the affinity beads in a concentration-dependent manner. The half-maximal effective concentrations, however were significantly (p<0.01) different being 0.32±0.02 μM and 0.71±0.02 μM for the VLC-1 and ALC-1 peptide, respectively. The appropriate scrambled peptides were without effect up to 3 μM. These results demonstrate the specific interaction between the N-terminal domains of human cardiac MLC-1 isoforms and actin and reveal different actin affinities of MLC-1 isoforms. Weak binding of ALC-1 to actin could explain the higher cycling kinetics of cross-bridges with ALC-1 compared to those with VLC-1.

【 授权许可】

Unknown