Enzymatic activities correlate with chimaeric substitutions at the actin-binding face of myosin

Taro Q.P. Uyeda, Kathleen M. Ruppel, James A. Spudich

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185 Citations (Scopus)

Abstract

MYOSINS are a functionally divergent group of mechanochemical enzymes involved in various motile activities in cells1. Despite a high degree of conservation in the amino-acid sequence of the 130K motor domain 2,3 (head region) of the molecule, there are large differences in the enzymatic and motile activities (Tables 1 and 2) of myosins from diverse species and cell types. However, the degree of conservation is not uniform throughout the head sequence4; therefore, one reasonable hypothesis is that the functional differences between myosins derive from the poorly conserved areas. The most prominent divergent region occurs at the 50K/20K junction, a region of the molecule sensitive to proteolytic digestion 5 and a binding site for actin6-12. We have now constructed chimaeras of this region of myosin by substituting the 9-amino-acid Dictyostelium junction region with those from myosins from other species and find that the actin-activated ATPase correlates well with the activity of the myosin from which the junction region was derived. Our results suggest that this region, likely to be part of the myosin head that interacts directly with actin10,13,14, is important in determining the enzymatic activity of myosin.

Original languageEnglish
Pages (from-to)567-569
Number of pages3
JournalNature
Volume368
Issue number6471
DOIs
Publication statusPublished - 1994
Externally publishedYes

ASJC Scopus subject areas

  • General

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