Cooperativity in F-actin: chemical modifications of actin monomers affect the functional interactions of myosin with unmodified monomers in the same actin filament

Ewa Prochniewicz-Nakayama, E. Katayama, T. Yanagida, David D Thomas

Research output: Contribution to journalArticle

50 Scopus citations

Abstract

We have chemically modified a fraction of the monomers in actin filaments, and then measured the effects on the functional interaction of myosin with unmodified monomers within the same filament. Two modifications were used: (a) covalent attachment of various amounts of myosin subfragment-1 (S1) with the bifunctional reagent disuccinimidyl suberate and (b) copolymerization of unmodified actin monomers with monomers cross-linked internally with 1-ethyl-3-(dimethylaminopropyl)-carbodiimide. Each of these modifications abolished the interaction of the modified monomers with myosin, so the remaining interactions were exclusively with unmodified monomers. The two modifications had similar effects on the interaction of actin with myosin in solution: decreased affinity of myosin heads for unmodified actin monomers, without a change in the Vmax of actin-activated myosin ATPase activity. However, modification (b) produced much greater inhibition of actin sliding on a myosin-coated surface, as measured by an in vitro motility assay. These results provide insight into the functional consequences of cooperative interactions within the actin filament.

Original languageEnglish (US)
Pages (from-to)113-123
Number of pages11
JournalBiophysical journal
Volume65
Issue number1
DOIs
StatePublished - 1993

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