Evidence against essential roles for subdomain 1 of actin in actomyosin sliding movements
- Department of Materials Processing, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-02, Sendai 980-8579 (Japan)
- Division of Biomolecular Imaging, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan)
- Gene Function Research Center, National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562 (Japan)
We have engineered acto-S1chimera proteins carrying the entire actin inserted in loop 2 of the motor domain of Dictyostelium myosin II with 24 or 18 residue-linkers (CP24 and CP18, respectively). These proteins were capable of self-polymerization as well as copolymerization with skeletal actin and exhibited rigor-like structures. The MgATPase rate of CP24-skeletal actin copolymer was 1.06 s{sup -1}, which is slightly less than the V {sub max} of Dictyostelium S1. Homopolymer filaments of skeletal actin, CP24, and CP18 moved at 4.7 {+-} 0.6, 2.9 {+-} 0.6, and 4.1 {+-} 0.8 {mu}m/s (mean {+-} SD), respectively, on coverslips coated with skeletal myosin at 27 deg C. Statistically thermodynamic considerations suggest that the S1 portion of chimera protein mostly resides on subdomain 1 (SD-1) of the actin portion even in the presence of ATP. This and the fact that filaments of CP18 with shorter linkers moved faster than CP24 filaments suggest that SD-1 might not be as essential as conventionally presumed for actomyosin sliding interactions.
- OSTI ID:
- 20710830
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 332, Issue 2; Other Information: DOI: 10.1016/j.bbrc.2005.04.152; PII: S0006-291X(05)00952-6; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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