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| 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. | | Language: | English | | Date of Publication (YYYY-MM-DD): | 1999-07-16 | | Title of Journal: | Journal of Molecular Biology | | Journal Abbrev.: | J. Mol. Biol. | | Volume: | 290 | | 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:http://www.idealibrary.com/links/doi/10.1006/jmbi.... [Abstract]
URI:http://www.idealibrary.com/links/doi/10.1006/jmbi.... [Fulltext PDF]
DOI:10.1006/jmbi.1999.2921 | |
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