Journal article
Hydrophobic loop dynamics and actin filament stability
Biochemistry (Easton), Vol.45(45), pp.13576-13584
11/14/2006
DOI: 10.1021/bi061229f
PMID: 17087511
Abstract
It has been postulated that the hydrophobic loop of actin (residues 262-274) swings out and inserts into the opposite strand in the filament, stabilizing the filament structure. Here, we analyzed the hydrophobic loop dynamics utilizing four mutants that have cysteine residues introduced at a single location along the yeast actin loop. Lateral, copper-catalyzed disulfide cross-linking of the mutant cysteine residues to the native C374 in the neighboring strand within the filament was fastest for S265C, followed by V266C, L267C, and then L269C. Site-directed spin labeling (SDSL) studies revealed that C265 lies closest to C374 within the filament, followed by C266, C267, and then C269. These results are not predicted by the Holmes extended loop model of F-actin. Furthermore, we find that disulfide cross-linking destroys L267C and L269C filaments; only small filaments are observed via electron microscopy. Conversely, phalloidin protects the L267C and L269C filaments and inhibits their disulfide cross-linking. Combined, our data indicate that, in solution, the loop resides predominantly in a "parked" position within the filament but is able to dynamically populate other conformational states which stabilize or destabilize the filament. Such states may be exploited within a cell by filament-stabilizing and -destabilizing factors.
Details
- Title: Subtitle
- Hydrophobic loop dynamics and actin filament stability
- Creators
- Damon Scoville - Department of Chemistry and Biochemistry and Molecular Biology Institute, University of California, Los Angeles, California 90095, USAJohn D StammDora Toledo-WarshaviakChristian AltenbachMartin PhillipsAlexander ShvetsovPeter A RubensteinWayne L HubbellEmil Reisler
- Resource Type
- Journal article
- Publication Details
- Biochemistry (Easton), Vol.45(45), pp.13576-13584
- Publisher
- United States
- DOI
- 10.1021/bi061229f
- PMID
- 17087511
- ISSN
- 0006-2960
- eISSN
- 1520-4995
- Grant note
- GM 077190 / NIGMS NIH HHS T32 EY07026 / NEI NIH HHS EY 05216 / NEI NIH HHS GM 33689 / NIGMS NIH HHS
- Language
- English
- Date published
- 11/14/2006
- Academic Unit
- Stead Family Department of Pediatrics; Biochemistry and Molecular Biology; Internal Medicine
- Record Identifier
- 9984024405102771
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