Evidence against essential roles for subdomain 1 of actin in actomyosin sliding movements
| Autor: | Md. Shahjahan P. Siddique, Takashi Miyazaki, Makoto Suzuki, Eisaku Katayama, Taro Q.P. Uyeda |
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| Rok vydání: | 2005 |
| Předmět: |
ATPase
Biophysics macromolecular substances Microfilament Filamin Biochemistry Myosin head Motion Structure-Activity Relationship Myosin Animals Dictyostelium Molecular Biology Actin Myosin Type II Binding Sites biology Molecular Motor Proteins Cell Biology Actomyosin biology.organism_classification Actins Recombinant Proteins Protein Structure Tertiary Crystallography Multiprotein Complexes biology.protein MDia1 Protein Binding |
| Zdroj: | Biochemical and biophysical research communications. 332(2) |
| ISSN: | 0006-291X |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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