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          Institute: MPI für medizinische Forschung     Collection: Abteilung Biophysik     Display Documents

ID: 22633.0, MPI für medizinische Forschung / Abteilung Biophysik
Role of the salt-bridge between switch-1 and switch-2 of Dictyostelium myosin
Translation of Title:Role of the salt-bridge between switch-1 and switch-2 of Dictyostelium myosin
Authors:Furch, Marcus; Fujita-Becker, Setsuko; Geeves, Michael A.; Holmes, Kenneth C.; Manstein, Dietmar J.
Date of Publication (YYYY-MM-DD):1999-07-16
Title of Journal:Journal of Molecular Biology
Journal Abbrev.:J. Mol. Biol.
Issue / Number:3
Start Page:797
End Page:809
Review Status:Peer-review
Audience:Experts Only
Intended Educational Use:No
Abstract / Description:Motifs N2 and N3, also referred to as switch-1 and switch-2, form part of the active site of molecular motors such as myosins and kinesins. In the case of myosin, N3 is thought to act as a γ-phosphate sensor and moves almost 6 Å relative to N2 during the catalysed turnover of ATP, opening and closing the active site surrounding the γ-phosphate. The closed form seems to be necessary for hydrolysis and is stabilised by the formation of a salt-bridge between an arginine residue in N2 and a glutamate residue in N3. We examined the role of this salt-bridge in Dictyostelium discoideum myosin. Myosin motor domains with mutations E459R or R238E, that block salt-bridge formation, show defects in nucleotide-binding, reduced rates of ATP hydrolysis and a tenfold reduction in actin affinity. Inversion of the salt-bridge in double-mutant M765-IS eliminates most of the defects observed for the single mutants. With the exception of a 2,500-fold higherKM value for ATP, the double-mutant displayed enzymatic and functional properties very similar to those of the wild-type protein. Our results reveal that, independent of its orientation, the salt-bridge is required to support efficient ATP hydrolysis, normal communication between different functional regions of the myosin head, and motor function.
External Publication Status:published
Document Type:Article
Communicated by:Wulf Kaiser
Affiliations:MPI für medizinische Forschung/Abteilung Biophysik/
Identifiers:URI: [Abstract]
URI: [Fulltext PDF]
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